Motion in a Straight Line — Physics STD 11 Science — Question

Why do spring balance shows wrong readings after they have been used for a long time?

We often say, "A current is going through the wire." What goes through the wire, the charge or the current?

When there is a collision between a negatively charged object and a positively charged object then what type of collision occurs?

Fill in the blanks:
The volume of a cube of side 1cm is equal to .....m³.

What is the method of transmission of heat without the help of any medium called?

If the earth did not have an atmosphere it would become intolerable cold. Why?

What will be the speed of sound in a perfectly rigid rod?

What is an epoch? Name the unit in which it is measured.

Given below are some examples of wave motion. State in each case if the wave motion is transverse, longitudinal or a combination of both:
(a) Motion of a kink in a longitudinal spring produced by displacing one end of the spring sideways.
(b) Waves produced in a cylinder containing a liquid by moving its piston back and forth.
(c) Waves produced by a motorboat sailing in water.
(d) Ultrasonic waves in air produced by a vibrating quartz crystal.