10 A proton and an alpha particle after being accelerated through same potential difference enter a uniform magnetic field the direction of which is perpendicular to their velocities Find the ratio of radii of the circular paths of the two particles 1 A solid sphere of radius R is floating in a liquid of density p with half of its volume submerged If the sphere is slightly pushed and released it starts performing simple harmonic motion Find the frequency of these oscillations 12 An object is approaching a thin convex lens of focal length 0 3 m with a speed of 0 01 m s Find the magnitudes of the rates of change of position and lateral magnification of image when the object is at a distance of 0 4 m from the lens 13 Draw the circuit for experimental verification of Ohm s using a source of variable D C voltage a main resistance of 10022 two galvanometers and two resistances of values 10 and 10 respectively Clearly show the positions of the voltmeter and the ammeter 14 A cube of coefficient of linear expansion a is floating in a bath containing a liquid of coefficient of volume expansiony When the temperature is raised by AT the depth upto which the cube is submerged in the liquid remains the same Find the relation between o and Y showing all the steps 15 One end of a rod of length L and cross sectional area A is kept in a fumace of temperature T The other end of the rod is kept at a temperature T The thermal conductivity of the material of the rod is K and emissivity of the rod is e It is given that T T AT where AT T T being the temperature of the surroundings If AT T T find the proportionality constant Consider that heat is lost only by radiation at the end where the temperature of the rod is T 16 Two blocks A and B of equal masses are released from an inclined plane of inclination 45 at t 0 Both the blocks are initially at rest The coefficient of kinetic friction between block A and the inclined plane is 02 while it is 19 In the circuit shown A and B are two cells of same emf E but different internal resistances r and r r r respectively Find the value of R such that the potential difference across the terminals of cell A is zero a long time after the key K is closed Pumace 0 3 for block B Initially the block A is 2m behind the block B When and where their front faces will come in a line Take g 10 m s 17 Wavelengths belonging to Balmer series lying in the range of 450 nm to 750 nm were used to eject photoelectrons from a metal surface whose work function is 2 0 eV Find in eV the maximum kinetic energy of the emitted photoelectrons Take hc 1242 eV nm 18 In a Young s double slit experiment two wavelengths of 500 nm and 700 nm were used What is the minimum distance from the central maximum where their maximas coincide again Take D d 10 Symbols have their usual meanings minumay 0 In a LR series circuit a sinusoidal voltage V V sin oot is applied VA It is given that L 35mH R 112 V V 220V 00 2m 50Hz and 1121 Mo anhyd 1 06 Lenina OPCHR