MARCH 2024 — Physics STD 12 Science — Question

The dispersive power of the material of lens of focal length 20 cm is 0.08. The longitudinal chromatic aberration of the lens is

(a) 0.08 cm

(b) 0.08/20 cm

(c) 1.6 cm

(d) 0.16 cm

Hole in semiconductor is:

If the energy of a photon corresponding to a wavelength of 6000 Å is 3.32 , the photon energy for a wavelength of 4000 Å will be

(a) 1.4 eV

(b) 4.9 eV

(c) 3.1 eV

(d) 1.6 eV

The dependence of binding energy per nucleon,  on the mass number, A, is represented by

(a)

(b)

(C)

(d)

If velocity of electron becomes equal to the velocity of light, then mass of electron will be:

Consider a current carrying wire (current I) in the shape of a circle. Note that as the current progresses along the wire, the direction of j (current density) changes in an exact manner, while the current I remain unaffected. The agent that is essentially responsible for is:

A battery of e.m.f. 3 volt and internal resistance 1.0 ohm is connected in series with copper voltameter. The current flowing in the circuit is 1.5 amperes. The resistance of voltameter will be

(a) Zero

(b) 1.0 ohm

(c) 1.5 ohm

(d) 2.0 ohm

The plane faces of two identical plano-convex lenses each having focal length of 40 cm are pressed against each other to form a usual convex lens. The distance from this lens, at which an object must be placed to obtain a real, inverted image with magnification one is

(a) 80 cm

(b) 40 cm

(c) 20 cm

(d) 162 cm

In an oscillating system, a restoring force is a must. In an L-C circuit, the restoring force is provided by a/ an.

Tungsten has work function 4.8 eV. We wish to use tungsten as photo-cathode with a 600 nm wavelength. What shall we do?