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 causes of energy loss in a transformer.
The two causes of energy loss in a transformer are as follow:
(i) Eddy Currents The alternating magnetic flux induces eddy currents in the iron core and causes heating.
(ii) Hysteresis loss because of repeated magnetisation and demagnetization
of the iron core.
(iii) The resistance of the windings The wire used for the windings has some resistance and so energy is lost due to heat produced in the wire (I2R).