Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Explain the behaviour of electric dipole in non-uniform electric field.

Define atomic mass unit (amu) and write its equivalent energy.

Do all the electrons that absorb a photon come out as photoelectrons?

Sound waves from a loudspeaker spread nearly uniformly in all directions if the wavelength of the sound is much larger than the diameter of the loudspeaker.

1. Calculate the frequency for which the wavelength of sound in air is ten times the diameter of the speaker if the diameter is 20cm.
2. Sound is essentially transmitted in the forward direction if the wavelength is much shorter than the diameter of the speaker. Calculate the frequency at which the wavelength of the sound is one tenth of the diameter of the speaker described above. Take the speed of sound to be 340m/s.

A tuning fork of frequency 256Hz produces 4 beats per second with a wire of length 25cm vibrating in its fundamental mode. The beat frequency decreases when the length is slightly shortened. What could be the minimum length by which the wire be shortened so that it produces no beats with the tuning fork?

Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 1.0 x10^–7 m² carrying a current of 1.5 A. Assume the density of conduction electrons to be 9 x10²⁸ m^–3.

Using figure. of the text, find the boiling point of methyl alcohol at 1atm (760mm of mercury) and at 0.5atm.

The atmospheric temperature in the cities on sea-coast change very little. Explain.