Question

(10) Answer the following questions in one sentence:-
(a) What is motion ?
(b) What does a speedometer measures ?
(c) Which device allows us to break and complete an
electric circuit ?
(d) Name two appliances that use electromagnets ?
(e) How many colors are there in a spectrum of white
light ?
(f) Which surface of concave mirror is silvered ?
(g) Why are concave and convex mirrors called spherical
mirrors ?
(h) Why we use nichrome in an electric heater ?
(i) What is fuse. Write it’s function?
(11) Write difference between real and virtual image ?
(12) What is the water pollution ? Write it’s main cause.
(13) Draw the diagram of electric bell. Write it’s construction.

Answer 1

Motion, in physics, change with time of the position or orientation of a body. 

there are seven colours in a spectrum of white light

the polished surface of concave mirror is slivered