Please answer all with work and explanations

. It is desired to use a magnetic field of 2.00 x 10~ teslas to produce a total magnetic flux of 6.28 x 10~* webers through a circular loop of wire. How should the loop be oriented rela- tive to the field if we want to achieve this with the smallest loop possible? (Draw a picture to express your answer.) What will be the radius of the wire loop required? 2 A square loop of wire connects the ends of a 10-ohm resistor, as shown. The loop sits perpendicular to a magnetic field of strength 0.6 T that is directed into the page in the picture at right. The field then drops to zero over a time of 3 seconds. If the loop is 10 cm high and 15 cm wide, what is the current induced in the loop? *3. A circular loop of wire sits face on to a 2-tesla magnetic field that points into the page, as shown in the upper diagram at right. The wire loop is turned a quarter turn by a crank, so that the right edge of the loop drops into the page and the left side of the loop comes out of the page. The radius of the loop is 20 cm and the quarter turn takes 0.5 seconds. a) What is the average emfinduced in the loop, and does the cur- rent in the wire flow in the direction of the arrow on the loop orin the opposite direction? b) If the crank continues to turn the loop another quarter turn in 0.5 seconds in the same direction, until it looks like the bottom picture, what will be the average emfinduced in the wire, and does the current in the wire flow in the direction of the arrow or in the opposite direction? *4. A bar is moved along conducting rails at a constant 2.0 m/s in the presence of a 1-tesla magnetic field into the page, as shown. A 4-ohm resistor is connected into the circuit. a) What current flows in the loop? b) What force is required to maintain the constant 2 m/s velocity?