ICSE Class X Important Questions of Physics
1. Write down the gravitational unit of force. How is it related to Newton?
2. A water pump raises 50 litres of water through a height of 25 m in 5 s. Calculate the power which the pump supplies. [Take g = 10 Nkg-1 and density of water = 1000kgm-1]
3. Name the three classes of levers and distinguish between them. Give two examples of each.
4. A man weighs 600 N on the earth. What would be his approximate weight on the moon? What is the reason for your answer?
5. Give an example when work done by the force of gravity acting on a body is zero even though the body gets displaced from its initial position.
1. If the power of a motor is 40 kW, at what speed can it raise a load of 20,000 N?
2. A ray of light, after refraction through a concave lens emerges parallel to the principal axis. Draw a ray diagram to show the incident ray and its corresponding emergent ray.
3. Draw a diagram to show how a converging lens can form a real and enlarged image of an object.
4. Water is used in hot water bottles for fomentation. Give reason for this.
5. How is the kinetic energy of a moving cart affected if (i) its mass is doubled, (ii) its velocity is is made equal to speed of light.
1. State two application of an echo.
2. How does the resistance of a wire depend on its radius? Explain your answer.
3. Why is a fuse always connected to the live wire in a circuit?
4. State Snell’s law of refraction.
5. State the factors on which the deviation produced by a prism depends.
1. State two differences between an electromagnet and a permanent magnet.
2. Steam at 100ºC is passed over 1000 g of ice at 0ºC. After some time, 600 g of ice at 0ºC is left and 450 g of water at 0ºC is formed. Calculate the specific latent heat of vaporisation of steam. [Sp. Latent heat of ice is 336 Jg-1 and sp. Heat capacity of water is 4.2 Jg-1K-1]
3. On what factors does the resistivty of a wire depend?
4. State two properties which are common to both beta rays and cathode rays.
5. Draw a ray diagram of an image formed by slide projecter.
1. What do you understand by the conservation of mechanical energy. 
2. Name a machine which is used to : (i) multiply force, (ii) multiply speed, and (iii) change the direction of force applied. 
3. A block and tackle system has the velocity ratio 3. A man can exert a pull of 200 kgf. What is the maximum load he can raise with this pulley system if its efficiency is 60%?
1. What is a prism? With the help of a diagram of a prism, indicate its refracting surfaces, refracting edge and base. 
2. Explain the working of dual switch with a neat diagram. 
3. A boy of mass 40 kg runs up a flight of 15 steps, each 15 cm high in 10 s. Find the work done and the power developed by him. Take g = 10 Nkg-1. 
1. Define the term critical angle and total internal reflection. State two conditions necessary for total internal reflection to occur. Write down the relation for the critical angle in terms of refractive index. 
2. Why do the qualities of sound of the same pitch differ when produced by different instruments? 
3. A large truck & a car both moving with a speed ‘v’ have ahead of collision and both of them come to halt after that,If the collision lasts for 10sec.
1. which vehicle experiences the greater force of impact?
2. which vehicle experiences the greater momentum change?
3. which vehicle experiences the greater acceleration?
4. why is the likely to suffer more damage than the car?
1. A bucket containing 8 kg of water at 25ºC. 2 kg of water at 80ºC is poured into it. Neglecting the heat energy absorbed by the bucket, calculate the final temperature of water. 
2. Why is the base of a cooking pan made thick and heavy? 
3. State with reason, which of the two, boiling water or steam both at 100ºC will produce more severe burns. 
1. Differentiate between the e.m.f. and terminal voltage of a cell. 
2. An electric iron is rated at 750 W, 230 V. Calculate the electrical energy consumed by the iron in 16 hours. If the cost of electricity is Rs.5 per unit, calculate the total cost. 
3. State four main ways by which the speed of rotation of an electric motor can be increased.