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

If light is passed through a double-slit opening and falls onto a screen, Identify the pattern produced on the screen.

What is mainly measured by potentiometer ?

The field due to a magnet at a distance R from the centre of the magnet is proportional to

(a)

(b)

(c)

(d)

A primary cell has an e.m.f. of 1.5 volts, when short-circuited it gives a current of 3 amperes. The internal resistance of the cell is

(a) 4.5 ohm

(b) 2 ohm

(c) 0.5 ohm

(d) 1/4.5 ohm

The threshold wavelength for photoelectric effect of a metal is 6500 Å. The work function of the metal is approximately

(a) 2 eV

(b) 1 eV

(c) 0.1 eV

(d) 3 eV

Which of the following particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field?

The magnetic flux linked with a circuit of resistance 100 ohm increases from 10 to 60 webers. The amount of induced charge that flows in the circuit is (in coulomb)

(a) 0.5

(b) 5

(c) 50

(d) 100

A magnetic field

(a) Always exerts a force on a charged particle

(b) Never exerts a force on a charged particle

(c) Exerts a force, if the charged particle is moving across the magnetic field lines

(d) Exerts a force, if the charged particle is moving along the magnetic field lines

What will be the focal length of a convex lens whose power is +2.5 D ?