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 characteristics of a good thermion emitter.
Two characteristics of a good thermion emitter are as follow:
(i) It should have low work function (the minimum energy required by an electron to just escape from the metal surface.) i.e. lesser the work functions of the emitter, more conveniently or easily, the electrons could be emitted with less energy applied.
(ii) It should have large surface area. So that more number of electrons could be emitted.