Electromagnetic Waves — Physics STD 12 Science — Question

When the light source is kept 20 cm away from a photo cell, stopping potential 0.6 V is obtained. When source is kept 40 cm away, the stopping potential will be(a) 0.3 V  (b) 0.6 V(c) 1.2 V   (d) 2.4 V

Huygen’s principle of secondary wavelets may be used to(a) Find the velocity of light in vacuum (b) Explain the particle behaviour of light(c) Find the new position of the wavefront(d) Explain photoelectric effect

The ratio of intensities of consecutive maxima in the diffraction pattern due to a single slit is

Which of the following is the definition for magnetic meridian of Earth?

Which of the following statement is correct(a) Both Peltier and Joule effects are reversible(b) Both Peltier and Joule effects are irreversible(c) Joule effect is reversible, whereas Peltier effect is irreversible(d) Joule effect is irreversible, whereas Peltier effect is reversible

Assertion  :   An aircraft flies along the meridian, the potential at the ends of its wings will be the same.
Reason     : Whenever there is change in the magnetic flux e.m.f. induces.(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.

An organ pipe, open at both ends, contains

1. Longitudinal stationary waves.
2. Longitudinal travelling waves.
3. Transverse stationary waves.
4. Transverse travelling waves.