# Physics 9th Class Important Questions

Physics Class 9th

Objective (2019)

(1) Which one of the following units is not a derived unit?

(A) Pascal

(B) Kilogramme

(C) Newton

(D) Watt

(2) Which of the following is a vector quantity?

(A) Speed

(B) Distance

(C) Displacement

(D) Power

(3) Inertia depends upon:

(A) Mass

(B) Force

(C) Net force

(D) Velocity

(4) The S.I unit of weight is:

(A) Watt

(B) Kilogramme

(C) Gramme

(D) Newton

(5) The number of perpendicular components of a force are:

(A) 1

(B) 2

(C) 3

(D) 4

(8) Earth’s gravitational force of attraction vanishes at:

(A) Infinity

(B) 6400 km

(C) 42300 km

(D) 4000 km

(7) One horse power is equal to:

(A) 674 watt

(B) 746 watt

(C) 647 watt

(D) 110 watt

(8) In Einstein’s mass-energy equation “C” is the:

(A) Speed of sound

(B) Speed of Earth

(C) Speed of electron

(D) Speed of light

(9) S.l unit of pressure is Pascal which is equal to:

(A) 104Nm-2

(8) 1 Nm-2

(C) 102Nm-2

(D) 103Nm-2

(10) Co-efficient of volume thermal expansion of Brass is:

(A) 6.0.x 10-5K-1

(B) 2.4x 10-5K-1

(C) 7.2x 10-5K-1

(D) 4.2x 10-5K-1

(11) Thermal conductivity of Copper is:

(A) 0.026 wm-1k-1

(B) 400 wm-1k-1

(C) 0.6 wm-1k-1

(D) 105 wm-1k-1

(12) Which of the following is a good radiator of heat?

(A) A white surface

(B) A shining silvered surface

(C) A green coloured surface

(D) A dull black surface

Subjective (2019) | Short Questions

1. Define Nuclear Physics and Plasma Physics.
2. Estimate 14 years age in seconds?
3. What is meant by Vernier Constant?
4. Differentiate between Scalars and Vectors.
5. Write two types of Motion.
6. White two differences between Mass and Weight.
7. Define Friction and Coefficient of Friction.
8. Define Force. What is the unit of force in S.I?
9. Define Like and Unlike parallel forces.
10. Differentiate between centre of mass and centre of gravity
11. State the Law of Gravitation.
12. What is meant by Field Force?
13. What are Satellites? Give one example.
14. Write unit of work and define this unit also.
15. What is meant by Nuclear Fuels?
16. Define Power. Write its formula.
17. Write important features of Kinetic molecular model of a matter.
18. Define Density. What is its St unit?
19. State Pascal’s law and write the name of its two applications.
20. Define Temperature and write ts SI Unit.
21. What is meant by upper and lower fixed point of Thermometer?
22. What is meant by transfer of heat?
23. What is meant by rate of flow of heat? Write its equation.
24. What is Styrofoam? Write its one use.

Long Questions

1. Derive third equation of motion with the help of speed-time graph.
2. How much time is required to change 22 Ns momentum in a body by a force 20 N?
3. Define Centre of gravity. how can you find the Centre of gravity of an irregular shaped thin lamina?
4. A motor boat moves at a steady speed of 4 ms-1. Water resistance acting on it is 4000 N Calculate the power of its engine.
5. Define Evaporation. Write the various factors affecting it.
6. A cube of glass of 5 cm side and mass 306 g. has a cavity inside it. If the density of glass 15 255 gem-3? Find the volume of the cavity.