The displacement–time graph of a sound wave produced by a vibrating wire is shown below.
Displacement
Q
P R Time
S
(a) How will you adjust the tension in the wire, to reduce the length of PR?
(b) Which characteristic of sound is affected by the reduction in the length of PR?

Choose the correct answers to the questions from the given options. [15] (Do not copy the questions, write the correct answers only.)
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

Choose the correct answers to the questions from the given options. [15] (Do not copy the questions, write the correct answers only.)
A body is acted upon by two equal and opposite forces, that are NOT along the same straight line. The
body will:

Choose the correct answers to the questions from the given options. [15] (Do not copy the questions, write the correct answers only.)
Which among the following is a vector quantity?

Choose the correct answers to the questions from the given options. [15] (Do not copy the questions, write the correct answers only.)
When a ray of light passes from one optical medium to another, which of the following physical quantities
does NOT change?

Choose the correct answers to the questions from the given options. [15] (Do not copy the questions, write the correct answers only.)
Which one of the following combinations is the correct ascending order of electromagnetic waves in
terms of wavelength?