Magnetism And Matter — Physics STD 12 Science — Question

The transverse nature of light is shown by:

The process in which a region is made free from any electric field is known as _____________.

Two uniform solid spheres having unequal masses and unequal radii are released from rest from the same height on a rough incline. If the spheres roll without slipping:

1. The heavier sphere reaches the bottom first.
2. The bigger sphere reaches the bottom first.
3. The two spheres reach the bottom together.
4. The information given is not sufficient to tell which sphere will reach the bottom first.

An ammeter, suspected to give inaccurate reading, is connected in series with a silver voltameter. The ammeter indicates 0.54 A. A steady current passed for one hour deposits 2.0124 gm of silver. If the E.C.E. of silver is 1.118 ,  then the error in ammeter reading is

(a) + 0.04 A

(b) + 0.02 A

(c) – 0.03 A

(d) – 0.01 A

The capacitance of a parallel plate capacitor is 12μF. If the distance between the plates is doubled and area is halved, then new capacitance will be

(a) 8μF

(b) 6μF

(c) 4μF

(d) 3μF

'Electrons revolve round the nucleus in well-defined orbits, like planets revolve round the sun' was the brainchild of:

An object is placed at a distance u from a simple microscope of focal length f. The angular magnification obtained depends:

1. On f but not on u.
2. On u but not on f.
3. On f as well as u.
4. Neither on f nor on u.

A body is rotating nonuniformity about a vertical axis fixed in an inertial frame. The resultant force on a particle of the body not on the axis is:

1. Vertical.
2. Horizontal and skew with the axis.
3. Horizontal and intersecting the axis.
4. None of these.

The minimum energy required to excite a hydrogen atom from its ground state is

(a) 13.6 eV

(b) -13.6 eV

(c) 3.4 eV

(d) 10.2 eV

Two different loops are concentric and lie in the same plane. The current in the outer loop is clockwise and increasing with time. The induced current in the inner loop then, is

(a) Clockwise

(b) Zero

(c) Counter clockwise

(d) In a direction that depends on the ratio of the loop radii