Power supply is transmitted at a very high voltage and low current in order to?
make pass through the trasformers
increase the power supply
make it travel fast
prevent overheating of the coil
Correct answer is D
H eat generated in a wire carrying current, H = 12 Rt.
so, when voltage is high and current is low heat generated in the wire will be minimal.
Therefore, high voltage and low current prevent overheating of the coil.
be induced
converge
diverge
remain constant
Correct answer is C
Since the charged rod is not in contact with the electroscope, the leaves divergence will diverge.
Dispersion occurs when white light passes through a glass prism because of the?
different hidden colours in the glass
different speeds of the colour in the glass
defects in the glass
high density of the glass
Correct answer is B
Dispersion is the splitting of white light into its spectral component colors and is caused by different speed of the colors in the prism.
Which of the following is used for the correction of short sightedness?
convex lens
concave lens
convex mirror
concave mirror
Correct answer is B
Concave lens diverges parallel rays of light. A short sighted person has the image formed before the retina,and the rays have to be diverged so that they intersect to form image onto the retina
The frequency of the wave in the diagram above is
0.17 Hz
0.25 Hz
1.57 Hz
1.05 Hz
Correct answer is B
Generally, period T = 1/f(reciprocal of frequency).
=> f = 1/T
And from the diagram, period T = 4s
∴ frequency, f = 1/T = 1/4 = 0.25 Hz
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