Moving Charges and Magnetism — Physics STD 12 Science — Question

If frequency of the incident photon on the metal surface is made double, then kinetic energy of the emitted photoelectron will become :

A nuclear reaction given by   represents

(a) g-decay

(b) Fusion

(c) Fission

(d) b-decay

A fish is a little away below the surface of a lake. If the critical angle is 49°, then the fish could see things above the water surface within an angular range of θ° where

(a) θ =  49°

(b) θ = 90°

(c) θ = 98°

(d) θ = 24

If in a nuclear fusion process the masses of the fusing nuclei be  and   and the mass of the resultant nucleus be , then

(a)

(b)

(c)

(d)

A hollow double concave lens is made of very thin transparent material.  It can be filled with air or either of two liquids L₁ and L₂ having refractive indices n₁ and n₂ respectively (n₂ > n₁ > 1).  The lens will diverge a parallel beam of light if it is filled with

(a) Air and placed in air	(b) Air and immersed in L1
(c) L1 and immersed in L2	(d) L2 and immersed in L1

To get line spectrum, the substances are excited in their:

Soap bubbles appear colored when seen in white light. The reason for this phenomenon is :

When the speed of electrons increases, then the value of its specific charge

(a) Increases

(b) Decreases

(c) Remains unchanged

(d) Increases upto some velocity and then begins to decrease

The fluorescence of the glass (discharge) tube at very low pressure is characteristic of ________:

A thermo couple uses Bismuth and Tellurium as the dissimilar metals. The sensitivity of bismuth is -72μV/℃  and that of the tellurium is 500μV/℃. If the difference between hot and cold junction is 100℃  then the maximum output will be

(a) 50 mV

(b) 7.2 mV

(c) 42.8 mV

(d) 57.2 mV