Wave Optics — Physics STD 12 Science — Question

Assertion  :   The phenomenon of ­X-ray production is basically inverse of photoelectric effect.    

Reason      :  X-rays are electromagnetic waves.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

Why the current does not rise immediately in a circuit containing inductance

(a) Because of induced emf	(b) Because of high voltage drop
(c) Because of low power consumption	(d) Because of Joule heating

A light ray is incident upon a prism in minimum deviation position and suffers a deviation of 34°.  If the shaded half of the prism is knocked off, the ray will

(a) Suffer a deviation of 34°	(b) Suffer a deviation of 68°
(c) Suffer a deviation of 17°	(d) Not come out of the prism

A capacitor 4 μF charged to 50  V is connected to another capacitor of 2 μF  charged to 100 V with plates of like charges connected together. The total energy before and after connection in multiples of  (  is

(a) 1.5 and 1.33

(b) 1.33 and 1.5

(c) 3.0 and 2.67

(d) 2.67 and 3.0

A 4μF conductor is charged to 400 volts and then its plates are joined through a resistance of 1kΩ. The heat produced in the resistance is

(a) 0.16 J

(b) 1.28 J

(c) 0.64 J

(d) 0.32 J

A concave lens of focal length 20 cm placed in contact with a plane mirror acts as a

(a) Convex mirror of focal length 10 cm

(b) Concave mirror of focal length 40 cm

(c) Concave mirror of focal length 60 cm

(d) Concave mirror of focal length 10 cm

When an input signal 1 is applied to a NOT gate, its output is:

Two different coils have self-inductance ,. The current in one coil is increased at a constant rate. The current in the second coil is also increased at the same rate. At a certain instant of time, the power given to the two coils is the same. At that time the current, the induced voltage and the energy stored in the first coil are  and  respectively. Corresponding values for the second coil at the same instant are  and   respectively. Then

(a)

(b)

(c)

(d) a, b, c

When an electron jumps from the fourth orbit to the second orbit, one gets the:

The sun is rotating about its own axis. The spectral lines emitted from the two ends of its equator, for an observer on the earth, will show

(a) Shift towards red end

(b) Shift towards violet end

(c) Shift towards red end by one line and towards violet end by other

(d) No shift