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

The internal resistances of two cells shown are 0.1 Ω  and 0.3 Ω. If R = 0.2 Ω, the potential difference across the cell

(a) B will be zero	(b) A will be zero
(c) A and B will be 2V	(d) A will be > 2V  and B will be < 2V

The electric field inside a conductor.

Magnetic field due to 0.1 A current flowing through a circular coil of radius 0.1 m and 1000 turns at the centre of the coil is

(a) 2

(b) 4.31

(c) 6.28

(d) 9.81

The de-Broglie wavelength of a tennis ball of mass 66 g moving with the velocity of 10 metre per second approximately:

The inability of a lens to bring all the rays coming from a point object to focus at one single point is called:

A parallel beam of monochromatic light is incident at one surface of a equilateral prism. Angle of incidence is 55° and angle of emergence is 46°. The angle of minimum deviation will be

(a) Less than 41°

(b) Equal to 41°

(c) More than 41°

(d) None of the above

A straight wire of length (  metre is carrying a current of 2A and the magnetic field due to it is measured at a point distant 1 cm from it. If the wire is to be bent into a circle and is to carry the same current as before, the ratio of the magnetic field at its centre to that obtained in the first case would be

(a) 50 : 1

(b) 1 : 50

(c) 100  : 1

(d) 1 : 100

Which of the following cannot travel in vacuum?

While tuning in a certain broadcast station with a receiver, we are actually

(a) Varying the local oscillator frequency

(b) Varying the frequency of the radio signal to be picked up

(c) Tuning the antenna

(d) None of these