A submarine in the sea, sends ultrasonic ping and a stopwatch is started. simultaneously. The stopwatch
stops on receiving the reflected wave from an obstacle and reads 1 minute 40 seconds. Calculate the
distance of the obstacle from the submarine (Speed of sound in water 1500 ms-1)

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What is the correct energy transformation during burning of a candle?

Copper wire is wound around a steel bar FT. Current is allowed to pass through the coil for some time
and then the bar is removed.
(a) Draw only the magnetised bar FT and mark its poles.
(b) Trace two magnetic lines of force around FT clearly indicating the direction.
F T

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A body is acted upon by two equal and opposite forces, that are NOT along the same straight line. The
body will:

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Which among the following is a vector quantity?

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When a ray of light passes from one optical medium to another, which of the following physical quantities
does NOT change?

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Which one of the following combinations is the correct ascending order of electromagnetic waves in
terms of wavelength?