(English Medium) ICSE Class 9 - CISCE Question Bank Solutions

The pitch of a screw gauge is 1 mm and the circular scale has 100 divisions. In measurement of the diameter of a wire, the main scale reads 2 mm and 45th mark on the circular scale coincides with the base line. Find

(i) The least count and

(ii) The diameter of the wire.

When a screw gauge with a least count of 0.01 mm is used to measure the diameter of a wire, the reading on the sleeve is found to be 1 mm and the reading on the thimble is found to be 27 divisions.

(i) What is the diameter of the wire in cm?

(ii) If the zero error is +0.005 cm, what is the correct diameter?

A screw gauge has 50 divisions on its circular scale and its screw moves by 1 mm on turning it by two revolutions. When the flat end of the screw is in contact with the stud, the zero of the circular scale lies below the base line and 4th division of the circular scale is in line with the base line. Find

(i) The pitch,

(ii) The least count and

(iii) The zero error of the screw gauge

Fig., below shows the reading obtained while measuring the diameter of a wire with a screw gauge. The screw advances by 1 division on the main scale when circular head is rotated once.  

Find:
(i) Pitch of the screw gauge,
(ii) Least count of the screw gauge and
(iii) The diameter of the wire.

A screw has a pitch equal to 0.5 mm. What should be the number of divisions on its head so as to read correctly up to 0.001 mm with its help?

A pendulum completes 2 oscillations in 5 s. What is its time period? If g = 9.8 m s^-2, find its length.

How can the least count of a screw gauge be decreased?

Figure (a) shows the displacement-time graph for the motion of a body. Use it to calculate the velocity of the body at t = 1 s, 2 s and 3 s, and then draw the velocity-time graph in Figure (b) for it.

(a)	(b)

What is meant by the renewable and non-­renewable sources of energy? State two differences between them, giving two examples of each

Select the renewable and non-renewable sources of energy from the following :

1. Coal
2. Wood
3. Water
4. Diesel
5. Wind
6. Oil

Why is the use of wood as a fuel not advisable although wood is a renewable source of energy?

Name five renewable and three non-renewable sources of energy.

Renewable source of energy is :

What is meant by the efficient use of energy?

State two ways to save the energy.

How does the proper insulation of home save energy?

Which of the following device is most efficient for the lighting purpose?

LED, CFL, fluorescent tube light, Electric bulb.

Give an example to explain that the use of modem eco-friendly technology is more efficient and less polluting.

Describe three ways for the efficient use of energy.

What social initiatives must be taken for the sensitive use of energy?