The diagrams given below show two sound boxes A and B with wires of same length (l) and tension (10
kgf) but different cross-sectional areas. Simultaneously, vibrating tuning forks of frequency 300 Hz are
placed on the boxes A and B. The paper rider falls off in case of B but not in case of A.
l l
A B
Paper rider Paper rider
10 kgf 10 kgf
(a) Name and explain the phenomenon responsible for the falling off of the paper rider in B.
(b) The wire A resonates with a tuning fork of frequency ‘f ’. Is ‘f ’ greater than, less than or equal to 300 Hz?
Justify your answer.

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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?