Advertisements
Advertisements
प्रश्न
An e.m. wave exerts pressure on the surface on which it is incident. Justify.
उत्तर
An e.m. wave carries momentum with itself and is given by
P = `"Energy of wave (U)"/"Speed of the wave (c)"`
= `"U"/"c"`
when it is incident upon a surface it exerts pressure on it.
APPEARS IN
संबंधित प्रश्न
State Moseley's law
Name two electromagnetic waves of frequency smaller than that of violet light. State one use of each.
The wavelength of X-rays is 0.01 Å. Calculate its frequency. State the assumption made, if any.
How are X-rays produced?
The energy of a photon of a characteristic X-ray from a Coolidge tube comes from
50% of the X-rays coming from a Coolidge tube are able to pass through a 0.1 mm thick aluminium foil. If the potential difference between the target and the filament is increased, the fraction of the X-rays passing through the same foil will be
X-ray incident on a material
(a) exerts a force on it
(b) transfers energy to it
(c) transfers momentum to it
(d) transfers impulse to it.
The stopping potential in a photoelectric experiment is linearly related to the inverse of the wavelength (1/λ) of the light falling on the cathode. The potential difference applied across an X-ray tube is linearly related to the inverse of the cutoff wavelength (1/λ) of the X-ray emitted. Show that the slopes of the lines in the two cases are equal and find its value.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
A bat moving at 10 ms−1 towards a wall sends a sound signal of 8000 Hz towards it. On reflection, it hears a sound of frequency f The value of f in Hz is close to (speed of sound = 320 ms−1)
