Electricity and Magnetism — PHYSICS STD 7 — Question

The diagram in Fig. shows an incident ray AO and the reflected ray OB from a plane mirror. The angle AOB is 30°. Draw normal on the plane mirror at the point O and find :

State the differences between regular and diffused reflection.

Give one example to show the conversion of potential energy to kinetic energy when put in use.

Describe an experiment to show that the angle of incidence is equal to the angle of- reflection.

Describe the construction of a thermos flask with the help of a neat diagram and label it.

Match the following

(a). A light ray passes             from air to glass	(1) . speeds up
(b). A light ray passes             from glass to water	(2). reflects red light
(c). Virtual image	(3). primary colours
(d). Red rose	(4). plane mirror
(e). Red, green, and               blue	(5). slows down

Describe an experiment to show that each source of sound is a vibrating body.

(a) State the law of conservation of energy.
(b) By giving an example explain law of conservation of energy.
(c) Show that the sum of potential energy and kinetic energy remains the same by giving the example of roller coaster car.

State the function of each of the following in an electric circuit and draw its symbolic representation: (1) Switch and (2) Cell.

Convert 40°C to the (a) Fahrenheit scale (b) Kelvin Scale.