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Physics Questions and Answers October 03, 2022

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In a double slit experiment, the two slits are 1 mm apart and the screen is placed 1 m away. A,monochromatic light wavelength 500 nm is used. What will be the width of each slit for obtaining ten maxima of double slit within the central maxima of single slit pattern (a) 0.1 mm (c) 0.02 mm (b) 0.5 mm (d) 0.2 mm

In a CE transistor amplifier, the audio signal voltage across the collector resistance of 2kQ2 is 2V. If the base resistance is 1k0 and the current amplification of the transistor is 100, the input signal voltage is (a) 0.1 V (c) 1 mV (b) 1.0 V (d) 10 mV

Two discs are rotating about their axes, normal to the discs and passing through the centres of the discs. Disc D, has 2 kg mass and 0.2 m radius and initial angular velocity of 50 rad s. Disc D, has 4kg mass, 0.1 m radius and initial angular velocity of 200 rad s. The two discs are brought in contact face to face, with their axes of rotation

A block of mass M is attached to the lower end of a vertical spring. The spring is hung from a ceiling and has force constant value k. The mass is released from rest with the spring initially unstretched. The maximum extension produced in the length of the spring will be (a) 2 Mgk (b) 4 Mgk (c) Mg2k (d) Mgk

An electron moves in a circular orbit with a uniform speed v. It produces a magnetic field B at the centre of the circle. The radius of the circle is proportional to (a) VYB LIB

The output from a NAND gate is divided into two in parallel and fed to another NAND gate. The resulting gate is a A DID (a) NOT gate (b) AND gate (c) NOR gate (d) OR gate

Turpentine oil is flowing through a tube of length 1 cm and radius r. 1127120 X 10N The pressure difference between the two ends of the tube is p. The viscosity of oil is given by p(r x) 4vl where v is the velocity of oil at a distance x from the axis of the tube. The dimensions of n are (a) MLOT (c) MLT (b) MLT (d) ML T

Two discs of same moment of inertia rotating about their regular axis passing through centre and perpendicular to the plane of disc with angular velocities 00 and . They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is (a)1(w w) (b) I(W W) (c)(WW) (d) 1 (w w)

Two waves are represented by the equations y, sin (oot kx 0.57) m and y, a cos (ot kx) m, where x is in meter and t in sec. The phase difference between them is (a) 1.0 radian (c) 1.57 radian (b) 1.25 radian (d) 0.57 radian

A wire carries a current. Maintaining the same current it is bent first to form a circular plane coil of one turn which produces a magnetic field B at the centre of the coil. The same length is now bent more sharply to give a double loop of smaller radius. The magnetic field at the centre of the double loop, caused by the same current is (a) 4B

A ball is thrown vertically upwards with an initial velocity of 30 m/s. What will be its velocity after 3 seconds and how high will it go?

A car traveling at a constant velocity of 50 m/s collides with a stationary truck and comes to rest after 0.5 seconds. Calculate the impulse imparted to the car during the collision.

A 50 kg crate is being pulled up a ramp at a constant velocity by a horizontal force of 200 N. The ramp makes an angle of 30 degrees with the horizontal. Calculate the friction force acting on the crate.

A ball is thrown vertically upwards from the roof of a building with an initial velocity of 20 m/s. Calculate the time it takes for the ball to reach its maximum height and the maximum height reached by the ball.

Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is (a) 14 (b) 12 (c) 11 (d) 15

A drum of radius R and mass M, rolls down without slipping along an inclined plane of angle 0. The frictional force (a) dissipates energy as heat (b) decreases the rotational motion (c) decreases the rotational and translational motion (d) converts translational energy to rotational energy

Which of the following equations represent a wave (a) y A sin ot (b) y Acos kx (c) y A sin (at bx c) (d) y A (wt kx)

1 (a) along oy (b) opposite to oy (c) along ox (d) opposite to ox,A very long straight wire carries a current I. At the instant when a charge Q at point P has velocity v, as shown, the force on the charge is

In a photoemissive cell, with exciting wavelength 2, the fastest electron has speed v. If the exciting wavelength is changed to, the speed of the fastest emitted electron will be (a) (34)2. v (b) (43)2. v (c) less than (43)2. v (d) greater than (43)2. v

A train of 150 metre long is going towards north direction at a speed of 10 ms. A parrot flies at the speed of 5 ms towards south direction parallel to the railway track. The time taken by the parrot to cross the train is (a) 12 sec (b) 8 sec (d) 10 sec (c) 15 sec

acceleration The due to gravity on the planet A is 9 times the acceleration due to gravity on planet B. A man jumps to a height of 2m on the surface of A. What is the height of jump by the same person on the planet B (b) m (d) 6 m (a) m (c) 18 m

A source of unknown frequency gives 4 beatss, when sounded with a source of known frequency 250 Hz. The second harmonic of the source of unknown frequency gives five beats per second, when sounded with a source of frequency 513 Hz. The unknown frequency is (a) 246 Hz (c) 260 Hz (b) 240 Hz (d) 254 Hz

of turns N, then magnetic moment of the coil, M is (a) NIA Ni (c) Current i is flowing in a coil of area A and number 2152 (d) NAi

A rectangular tank with length 1.2 m, width 0.8 m and height 0.6 m contains oil of density 840 kg/m^3. Calculate the total force exerted by the oil on one of the end walls of the tank.

A horizontal pipe has a diameter of 0.05 meters and is filled with water flowing at a velocity of 2 m/s. Calculate the Reynolds number for the flow of water.

A cylindrical container of radius 0.05 m and height 0.15 m is filled with water to a height of 0.1 m. Determine the pressure at the bottom of the container.

A train moving at 50 m/s covers a distance of 200 meters while applying the brakes, coming to a stop. Calculate the acceleration of the train and the time taken to come to a stop.

A stone is dropped from a bridge into a river below. The sound of the splash is heard 3 seconds after the stone was dropped. If the speed of sound in air is 340 m/s, calculate the height of the bridge.

(c) directly proportional (d) directly proportional to mass M to M, X M,In a Rutherford scattering experiment when a projectile of charge Z, and mass M,approaches a target nucleus of charge Z, and mass M, the distance of closest approach is r. The energy of the projectile is (a) directly proportional to Z, Z (b) inversely proportional to Z,

The radii of circular orbits of two satellites A and B of the earth, are 4R and R, respectively. If the speed of satellite A is 3 V, then the speed of satellite B will be (a) 3 V4 (c) 12 V (b) 6 V (d) 3 V2

A star, which is emitting radiation at a wavelength of 5000 , is approaching the earth with a velocity of 1.50 x 10 ms. The change in wavelength of the radiation as received on the earth is (a) 0.25 (c) 25 (b) 2.5 (d) 250

In a coil of resistance 10 2, the induced current developed by changing magnetic flux through it, is shown in figure as a function of time. The magnitude of change in flux through the coil in Weber is ((amp) (a) 8 (c) 6 0.1 (b) 2 (d) 4

Energy E of a hydrogen atom with principal quantum number n is given by E 13.6n eV. The energy of photon ejected when the electron jumps from n 3 state to n 2 state of hydrogen is approximately (a) 1.9 eV. (c) 0.85 eV (b) 1.5 eV (d) 3.4 eV

A projectile is fired at an angle of 45 with the horizontal. Elevation angle of the projectile at its highest point as seen from the point of projection is (a) 60 (b) tan (1),(c) tan1 2 (d) 45

In rising from the bottom of a lake, to the top, the temperature of an air bubble remains unchanged, but its diameter gets doubled. If h is the barometric height (expressed in m of mercury of relative density p) at the surface of the lake, the depth of the lake is (a) 8 ph m (c) 9 ph m (b) 7ph m (d) 12 ph m

The total charge induced in a conducting loop when it is moved in a magnetic field depends on (a) the rate of change of magnetic flux (b) initial magnetic flux only (c) the total change in magnetic flux (d) final magnetic flux only

The volume occupied by an atom is greater than the volume of the nucleus by a factor of about 2003 (a) 105 (c) 10 (b) 10 (d) 100

A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using 2013 (a) Wiens displacement law (b) Kirchoffs law (c) Newtons law of cooling (d) Stefans law

A coil of 40 henry inductance is connected in series with a resistance of 8 ohm and the combination is joined to the terminals of a 2 volt battery. The time constant of the circuit is 2004 (a) 20 seconds (c) 15 seconds (b) 5 seconds (d) 40 seconds

In the reaction, 2H 3H He 1n, if the binding energies of 2H,3H and 4He are respectively, a, b and c (in MeV), then the energy (in MeV) released in this reaction is (a) a b c (b) a b c (c) c a b (d) c a b

A person of mass 60 kg is inside a lift of mass 940 kg and presses the button on control panel. The lift starts moving upwards with an acceleration 1.0 ms. If g 10 ms, the tension in the supporting cable is (b) 9680 N (d) 1200 N (a) 8600 N (c) 11000 N

The half life of a radioactive isotope X is 20 years. It decays to another element Y which is stable. The two elements X and Y were found to be in the ratio of 1 7 in a sample of a the given rock. The age of the rock is estimated to be (a) 60 years (c) 100 years (b) 80 years (d) 40 years

If delta.U and delta.W represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true (a) AU AW, in an adiabatic process (b) AUAW, in an isothermal process (c) AU AW, in an adiabatic process (d) AU AW, in an isothermal process

A reversible engine converts onesixth of the heat input into work. When the temperature of the sink is reduced by 62C, the efficiency of the engine is doubled. The temperatures of the source and sink are (a) 99C, 37C (c) 95C, 37C (b) 80C, 37C (d) 90C, 37C

The thermo e.m.f E in volts of a certain thermocouple is found to vary with temperature difference 0 in C between the two junctions according to the relation E 300 The neutral (a) 30 C (c) 400 C 0 15 temperature for the thermocouple will be (b) 450 C (d) 225 C

A concave mirror of focal length f is placed at a distance of d from a convex lens of focal length . A beam of light coming from infinity and falling on this convex lensconcave mirror combination returns to infinity. The distance d must equal (a) f f (c) 2f f (b)f f (d) 2f f

If a small amount of antimony is added to germanium crystal (a) it becomes a ptype semiconductor (b) the antimony becomes an acceptor atom (c) there will be more free electrons than holes in the semiconductor (d) its resistance is increased

Water falls from a height of 60 m at the rate of 15 kgs to operate a turbine. The losses due to frictional force are 10 of energy. How much power is generated by the turbine(g 10 ms) (a) 8.1 kW (c) 12.3 kW (b) 10.2 kW (d) 7.0 kW

The mean free path of molecules of a gas, (radius r) is inversely proportional to (a) r (b) r (c) r (d) r

Power dissipated across the 802 resistor in the circuit shown here is 2 watt. The power dissipated in watt units across the 302 resistor is 302 (a) 1.0 (c) 3.0 102 www www 802 (b) 0.5 (d) 2.0

In forward bias, the width of potential barrier in a pn junction diode (a) increases (b) decreases (c) remains constant (d) first 1 then 2

Which of the following statements are correct 2017 (A) Centre of mass of a body always coincides with the centre of gravity of the body (B) Centre of mass of a body is the point at which the total gravitational torque on the body is zero,(C) A couple on a body produce both translational and rotation motion in a body (D) Mechanical advantage

Two simple harmonic motions act on a particle. These harmonic motions are x A cos (oot 8), y A TL cos (oot a) when 8 a , the resulting motion is (a) a circle and the actual motion is clockwise (b) an ellipse and the actual motion is counterclockwise (c) an elllipse and the actual motion is clockwise (d) a circle and the actual motion is

In the circuit shown the cells A and B have negigible resistances. For V 12V, R 50092 and R 1000 the galvanometer (G) shows no deflection. The value of Vis A R (a) 4 V (c) 12 V www R (b) 2 V (d) 6 V

Two slits in Youngs experiment have widths in the ratio 125. The ratio of intensity at the maxima and minima in the interference pattern, is Imax Imin 121 14994

Transfer characteristics output voltage (V) vs input voltage (V) for a base biased transistor in CE configuration is as shown in the figure. For using transistor as a switch, it is used 2012 III N (a) in region III (b) both in region (I) and (III) (c) in region II (d) in region (I)

When a mass is rotating in a plane about a fixed point, its angular momentum is directed along 2012 (a) a line perpendicular to the plane of rotation (b) the line making an angle of 45 to the plane of rotation (c) the radius (d) the tangent to the orbit

A point performs simple harmonic oscillation of period T and the equation of motion is given by x a sin (oot 6). After the elapse of what fraction of the time period the velocity of the point will be equal to half of its maximum velocity (a) T8 (c) T3 (b) T6 (d) T12

If the kinetic energy of the particle is increased to 16 times its previous value, the percentage change in the deBroglie wavelength of the particle is (a) 25 (c) 60 (b) 75 (d) 50

The output(X) of the logic circuit shown in figure will be A B (a) X A. B (b) X A.B (c) X A B (d) X A B X

P represents radiation pressure, c represents speed of light and S represents radiation energy striking unit area per sec. The non zero integers x, y, z such that P S c is dimensionless are (a) x 1, y 1, z 1 (c) x 1, y 1, z 1 (b) x 1, y 1,z1 (d) x 1, y 1, z1

From a disc of radius R and mass M, a circular hole of diameter R, whose rim passes through the centre is cut. What is the moment of inertia of the remaining part of the disc about a perpendicular axis, passing through the centre (a) 15 MR32 (c) 11 MR32 (b) 13 MR32 (d) 9 MR32

Sound waves travel at 350 ms through a warm air and at 3500 ms through brass. The wavelength of a 700 Hz acoustic wave as it enters brass from warm air (a) decreases by a factor 10 (c) increases by a factor 10 (b) increases by a factor 20 (d) decreases by a factor 20

Two long parallel wires P and Q are both perpendicular to the plane of the paper with distance of 5 m between them. If P and Q carry currents of 2.5 amp and 5 amp respectively in the same direction, then the magnetic field at a point halfway between the wires is (a) (b) 2 Ho 3o (c) 2 (d) 2

Photoelectric emmision occurs only when the incident light has more than a certain minimum (a) power (b) wavelength (c) intensity (d) frequency

The displacement x (in meter) of a particle of mass m (in kg) moving in one dimension under the action of a force, is related to time t (in sec) by t x 3. The displacement of the particle when its velocity is zero, will be NEET Kar. 2013 (a) 2 m (c) zero (b) 4 m (d) 6 m

A solid cylinder of mass m and radius R rolls down an inclined plane of height h without slipping. The speed of its centre of mass when it reaches the bottom is (a) (2gh) (b) (d) 4gh 3 3gh 9

A wave of frequency 100 Hz is sent along a string towards a fixed end. When this wave travels back after reflection, a node is formed at a distance of 10 cm from the fixed end of the string. The speeds of incident (and reflected) waves are (a) 5 ms (c) 20 ms (b) 10 ms (d) 40 ms

A particle having charge q moves with a velocity V through a region in which both an electric field E and a magnetic fieldB are present.The force on the particle is (a) q q(B xv) (b) q. (B xv) (c) qvq(Ex B) (d) qE q(V x B)

The 21 cm radio wave emitted by hydrogen in interstellar space is due to the interaction called the hyperfine interaction in atomic hydrogen. The energy of the emitted wave is nearly 1998 (a) 10 J (c) 7 10 J (b) 1 J (d) 1024 J

A stone falls freely under gravity. It covers distances h, h and h, in the first 5 seconds, the next 5 seconds and the next 5 seconds respectively. The relation between h, h, and h, is h h3 (a) hl 3 5 (b) h 3h, and h 3h h, (c) h hh (d) h 2h, 3h

Assuming earth to be a sphere of uniform density, what is the value of g in a mine 100 km below the earths surface (Given, R 6400 km) 2001 (a) 9.65 ms (c) 5.06 ms (b) 7.65 ms (d) 3.10 ms

Two sources P and Q produce notes of frequency 660 Hz each. A listener moves from P to Q with a speed of 1 ms. If the speed of sound is 330 ms, then the number of beats heard by the listener per second will be,(a) zero (c) 8 (b) 4 (d) 2

A bar magnet, of magnetic moment M, is placed in a magnetic field of induction B. The torque exerted on it is (a) M. B (c) MX B (b)M. B (d) B x M

The vector sum of two forces is perpendicular to their vector differences. In that case, the forces (a) cannot be predicted (b) are equal to each other (c) are equal to each other in magnitude (d) are not equal to each other in magnitude

Two satellites of earth, S, and S, are moving in the same orbit. The mass of S, is four times the mass of S. Which one of the following statements is true,(a) The potential energies of earth satellites in the two cases are equal. (b) S, and S, are moving with the same speed. (c) The kinetic energies of the two satellites are equal. (d) The time

Two trains move towards each other with the same speed. The speed of sound is 340 ms. If the height of the tone of the whistle of one of them heard on the other changes 98 times, then the speed of each train should be (a) 20 ms (b) 2 ms (c) 200 ms (d) 2000 ms

A particle of mass m is projected with velocity v making an angle of 45 with the horizontal. When the particle lands on the level ground the magnitude of the change in its momentum will be 2008 (a) 2mv mv (b) 2 (c) mv2 (d) zero

The compressibility of water is 4 10 per unit atmospheric pressure. The decrease in volume of 100 cm of water under a pressure of 100 atmosphere will be (a) 0.4 cm (b) 4 x 105 cm (c) 0.025 cm (d) 0.004 cm

The current in self inductance L 40 mH is to be increased uniformly from 1 amp to 11 amp in 4 milliseconds. The e.m.f. induced in the inductor during the process is (a) 100 volt (c) 4.0 volt (b) 0.4 volt (d) 440 volt

M and M represent mass of neutron and proton respectively. If an element having atomic mass M has N neutron and Zproton, then the correct relation will be (a) M NM ZM (c) M NM ZM (d) M NM M

An electric fan has blades of length 30 cm measured from the axis of rotation. If the fan is rotating at 120 rpm, the acceleration of a point on the tip of the blade is (a) 1600 ms (c) 23.7 ms (b) 47.4 ms (d) 50.55 ms

Two metal rods 1 and 2 of same lengths have same temperature difference between their ends. Their thermal conductivities are K, and K, and cross sectional areas A and A, respectively. If the rate of heat conduction in rod 1 is four times that in rod 2, then (a) K,A KA (c) K,A, 2K,A, (b) K, A, 4K,A (d) 4K,A KA

Three charges, each q, are placed at the corners of an isosceles triangle ABC of sides BC and AC, 2a. D and E are the mid points of BC and CA. The work done in taking a charge Q from D to E is 3qQ 8ga qQ (a) (b) (c) zero 3qQ (d) 4 4a D C

In a series resonant circuit, having L, C and R as its elements, the resonant current is i. The power dissipated in the circuit at resonance is 2002 (a) iR (WL1C) (b) zero (c) iwL (d) iR where is the angular resonance frequency.

4N 3 (c) N 30 (60 IN 2N Three forces acting on a body are shown in the figure. To have the resultant force only along the y direction, the magnitude of the minimum additional force needed is (a) 0.5 N (b) 1.5 N (d) 3N

Thermal capacity of 40 g of aluminium (s 0.2 cal g K) is (a) 168 joule C (c) 840 jouleC (b) 672 jouleC (d) 33.6 jouleC

A capacitor is charged to store an energy U. The charging battery is disconnected. An identical capacitor is,now connected to the first capacitor in parallel. The energy in each of the capacitor is (a) U 2 (b) 3U2 (c) U (d) U 4

The electric field part of an electromagnetic wave in a medium is represented by E0 106 rad) t ( 102 rad)x Ey 2.5cos (2 x 106 (2 E 0. The wave is (a) moving along x direction with frequency 10 Hz and wave length 100 m. (b) moving along x direction with frequency 10 Hz and wave length 200 m. (c) moving along x direction with frequency 10 Hz and

aparticles, Bparticles and yrays are all having same energy. Their penetrating power in a given medium in increasing order will be NEET Kar. 2013 (a) B, y, a (b) y, a, (c) , B, Y (d) B, a, y

2 Two stones of masses m and 2 m are whirled in horizontal circles, the heavier one in radius and the lighter one in radius r. The tangential speed of lighter stone is n times that of the value of heavier stone when they experience same centripetal forces. The value of n is (a) 3 (c) 1 (b) 4 (d) 2

In thermodynamic processes which of the following statements is not true (a) In an isochoric process pressure remains constant (b) In an isothermal process the temperature remains constant (c) In an adiabatic process PVY constant (d) In an adiabatic process the system is insulated from the surroundings

A 12 cm wire is given a shape of a right angled triangle ABC having sides 3 cm, 4 cm and 5 cm as shown in the figure. The resistance between two ends (AB, BC, CA) of the respective sides are measured one by one by a multimeter. The resistances will be in the ratio of NEET Kar. 2013 (a) 345 (c) 273235 cm B 5 cm C (b) 91625 (d) 212425 4 cm

A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is (a) 10 cm (b) 15 cm (d) 5 cm (c) 2.5 cm

The efficiency of a Carnot engine operating between the temperatures of 100C and 23C will be 10023 (a) 100 (b) (c) (d) 10023 100 373250 373 373250 373

See the electric circuit shown in the figure. R www Which of the following equations is a correct equation for it (a) , i, r , i, r 0 0 (c) , (i, i) R i r0 (b) (i i) R i r (d) (i, i,) R i, r 0

A biconvex lens has a radius of curvature of magnitude 20 cm. Which one of the following options,best describe the image formed of an object of height 2 cm placed 30 cm from the lens (a) Virtual, upright, height 1 cm (b) Virtual, upright, height 0.5 cn. (c) Real, inverted, height 4 cm (d) Real, inverted, height 1cm

The amount of heat energy required to raise the temperature of 1g of Helium at NTP, from T.K to TK is (a) Nk (TT) a B 2 2 3 (b) Nk (TT.) a 4 3 (c) Nk 4 a 3 T BT1 (d) Nk, (TT) a B

A 5ampere fuse wire can withstand a maximum power of 1 watt in the circuit. The resistance of the fuse wire is (a) 0.04 ohm (c) 5 ohm (b) 0.2 ohm (d) 0.4 ohm

A depletion layer consists of (a) electrons (b) protons (c) mobile ions (d) immobile ions