Alternating Current — Physics STD 12 Science — Question

Which of the sets given below may represent the magnitudes of three vectors adding to zero?

1. 2, 4, 8
2. 4, 8, 16
3. 1, 2, 1
4. 0.5, 1, 2

The magnetic susceptibility of any paramagnetic material changes with absolute temperature T as(a) Directly proportional to T(b) Remains constant(c) Inversely proportional to T(d) Exponentially decaying with T

For two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.

In which radioactive disintegration, neutron dissociates into proton and electron

The angle which subtends the periphery of the spherical mirror at the centre of curvature is called:

Dimensions of permeability is :

A person is in a room whose ceiling and two adjacent walls are mirrors. How many images are formed(a) 5(b) 6(c) 7(d) 8

You are given three bulbs of 25, 40 and 60 watt. Which of them has lowest resistance(a) 25 watt bulb(b) 40 watt bulb(c) 60 watt bulb(d) Information is insufficient

A rectangular coil 20 cm × 20 cm  has 100 turns and carries a current of 1 A. It is placed in a uniform magnetic field       B  = 0.5 T with the direction of magnetic field parallel to the plane of the coil. The magnitude of the torque required to hold this coil in this position is(a) Zero  (b) 200 N-m(c) 2 N-m  (d) 10 N-m