Ray Optics and Optical Instruments — Physics STD 12 Science — Question

A person sitting firmly over a rotating stool has his arms stretched. If he folds his arms, his angular momentum about the axis of rotation:

1. Increases.
2. Decreases.
3. Remains unchanged.
4. Doubles.

Vapour is injected at a uniform rate in a closed veseel which was initially evacuated. The pressure in the vessel:

1. Increaaes continuously.
2. Decreases continuously.
3. First increases and then decreases.
4. First increases and then becomes constant.

Let Q and W denote the amount of heat given to an ideal gas and the work done by it in an adiabatic process.

1. Q = 0
2. W = 0
3. Q = W
4. Q ≠ W

A narrow beam of white light goes through a slab having parallel faces.

In a lossless transformer an alternating current of  2 amp is flowing in the primary coil. The number of turns in the primary and secondary coils are 100 and 20 respectively. The value of the current in the secondary coil is(a) 0.08 A(b) 0.4 A(c) 5 A(d) 10 A

......... Charge is produced by friction

To increase the angular magnification of a simple microscope, one should increase:

1. The focal length of the lens.
2. The power of the lens.
3. The aperture of the lens.
4. The object size.

Two identical charged spherical drops each of capacitance C merge to form a single drop. The resultant capacitance is(a) Equal to 2C (b) Greater than 2C (c) Less than 2C but greater than C(d) Less than C