Draw a ray diagram to show the refraction of a monochromatic ray through a prism when it suffers minimum deviation.
The human ear can detect continuous sounds in the frequency range from 20 Hz to 20,000 Hz. Assuming that the speed of sound in air is 330 ms-1 for all frequencies; calculate the wavelengths corresponding to the given extreme frequencies of the audible range.
An enemy plane is at a distance of 300 km from a radar. In how much time the radar will be able to detect the plane? Take velocity of radio waves as x 108 ms-1.
How is the frequency of a stretched string related to:
(i) it’s length
(ii) it’s tension?
An electric bulb of 300 Ω draws a current of 0.4 A. Calculate the power of the bulb and the potential difference at its ends.
State two factors upon which the rate of emission of thermions depends?
The rate of thermionic emission of electrons (number of electrons emitted per second) from a surface depends on the following factors, given as follow,
(i) Nature of the Metal Surface: Lower the work function of the metal, greater is the rate of emission of electrons from its surface.
(ii) The temperature of the Surface: Higher the temperature of the surface, greater is the rate of emission of electrons from the surface.