Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

In a Young’s double slit experiment, the source illuminating the slits is changed from blue to violet. The width of the fringes

(a) Increases

(b) Decreases

(c) Becomes unequal

(d) Remains constant

When a comb rubbed with dry hair attracts pieces of paper. This is because the.

The concept of stationary orbits was proposed by

(a) Neil Bohr

(b) J.J. Thomson

(c) Ruther ford

(d) I. Newton

If in the circuit shown below, the internal resistance of the battery is 1.5 W and V_P and V_Q are the potentials at P and Q respectively, what is the potential difference between the points P and Q

(a)  Zero

(b) 4 volts (VP > VQ)

(c) 4 volts (VQ > VP)

(d) 2.5 volts (VQ > VP)

Two lenses of power + 12 and – 2 diopters are placed in contact. The combined focal length of the combination will be

(a) 8.33 cm

(b) 1.66 cm

(c) 12.5 cm

(d) 10 cm

A radioactive nucleus is being produced at a constant rate a per second. Its decay constant is l. If N₀ are the number of nuclei at time t = 0, then maximum number of nuclei possible are

(a)

(b)

(c) N0

(d)

The fact that electric charges are integral multiples of the fundamental electronic charge was proved experimentally by

(a) Planck

(b) J.J. Thomson

(c) Einstein

(d) Millikan

The radius of the nucleus is smaller than the radius of the atom, approximately :

Bragg’s law for X-rays is

(a) d sin θ = 2n λ

(b) 2dsin θ = n λ

(c) n sin θ = 2 λ d

(d) None of these

For principal quantum number n = 3, the possible values of orbital quantum number ‘l’ are

(a) 1, 2, 3

(b) 0, 1, 2, 3

(c) 0, 1, 2

(d) –1, 0, +1