10th Science

NUMERICAL PROBLEMS:

10th Science NUMERICAL PROBLEMS:

1. Calculate the velocity of a moving body of mass 5 kg whose linear momentum is 2.5 kg m

s

–1

.

2. A door is pushed, at a point whose distance from the hinges is 90 cm, with a force of 40

N. Calculate the moment of the force about the hinges.

3. Two bodies have a mass ratio of 3:4 The force applied on the bigger mass produces an

acceleration of 12 ms-2.What could be the acceleration of the other body, if the same force

acts on it

4. A mechanic unscrew a nut by applying a force of 140 N with a spanner of length 40 cm.

What should be the length of the spanner if a force of 40 N is applied to unscrew the same

nut?

5. A beam of light passing through a diverging lens of focal length 0.3m appear to be

focused at a distance 0.2m behind the lens. Find the position of the object.

6. An object is placed at a distance 20cm from a convex lens of focal length 10cm. Find the

image distance and nature of the image.

7. An object of height 3cm is placed at 10cm from a concave lens of focal length 15cm.

Find the size of the image

8. A person with myopia can see objects placed at a distance of 4m. If he wants to see

objects at a distance of 20m, what should be the focal length and power of the concave

lens he must wear?

9. For a person with hyper meteropia, the near point has moved to 1.5m. Calculate the focal

length of the correction lens in order to make his eyes normal.

10. A container whose capacity is 70 ml is filled with a liquid up to 50 ml. Then, the liquid in

the container is heated. Initially, the level of the liquid falls from 50 ml to 48.5 ml. Then

we heat more, the level of the liquid rises to 51.2 ml. Find the apparent and real

expansion

11. Calculate the coefficient of cubical expansion of a zinc bar. Whose volume is increased

0.25 m3 from 0.3 m3 due to the change in its temperature of 50 K.

12. A charge of 12 coulomb fl ows through a bulb in 5 second. What is the current through

the bulb?

13. The work done in moving a charge of 10 C across two points in a circuit is 100 J. What

is the potential difference between the points?

14. Calculate the resistance of a conductor through which a current of 2 A passes, when the

potential difference between its ends is 30 V.

15. The resistance of a wire of length 10 m is 2 ohm. If the area of cross section of the wire

is 2 × 10–7 m

2

, determine its (i) resistivity (ii) conductance and (iii) conductivity

16. Three resistors of resistances 5 ohm, 3 ohm and 2 ohm are connected in series with 10 V

battery. Calculate their effective resistance and the current flowing through the circuit.

17. An electric heater of resistance 5 Ω is connected to an electric source. If a current of 6 A

flows through the heater, then find the amount of heat produced in 5 minutes

18. Calculate the current and the resistance of a 100 W, 200 V electric bulb in an electric

circuit.

19. Two resistors when connected in parallel give the resultant resistance of 2 ohm; but

when connected in series the effective resistance becomes 9 ohm. Calculate the value of

each resistance.

20. How many electrons are passing per second in a circuit in which there is a current of 5 A?

21. At what temperature will the velocity of sound in air be double the velocity of sound in

air at 0o C?

22. A source producing a sound of frequency 500 Hz is moving towards a listener with a

velocity of 30 m s–1

. The speed of the sound is 330 m s–1

. What will be the frequency

heard by listener?

23. A sound wave has a frequency of 200 Hz and a speed of 400 m s–1 in a medium. Find

the wavelength of the sound wave.

24. A strong sound signal is sent from a ship towards the bottom of the sea. It is received

back after 1s.What is the depth of sea given that the speed of sound in water 1450 m s–1

?

25. 92U 235 experiences one α – decay and one β – decay. Find number of neutrons in the final

daughter nucleus that is formed.

26. Calculate the amount of energy released when a radioactive substance undergoes fusion

and results in a mass defect of 2 kg

27. A cobalt specimen emits induced radiation of 75.6 millicurie per second. Convert this

disintegration in to becquerel (one curie = 3.7 × 1010Bq)

Detailed questions:

1. What are the types of inertia? Give an example for each type.

2. Deduce the equation of a force using Newton‟s second law of motion.

3. State and prove the law of conservation of linear momentum.

4. Describe rocket propulsion.

5. State the universal law of gravitation and derive its mathematical expression

6. Give the applications of gravitation

7. List any five properties of light

8. Differentiate the eye defects: Myopia and Hypermetropia

9. Explain the construction and working of a „Compound Microscope‟.

10. Explain the construction and working of a „simple Microscope‟.

11. Derive the ideal gas equation.

12. Explain the experiment of measuring the real and apparent expansion of a liquid with

a neat diagram.

13. With the help of a circuit diagram derive the formula for the resultant resistance of

three resistances connected: a) in series and b) in parallel

14. a) State Joule‟s law of heating.

b) An alloy of nickel and chromium is used as the heating element. Why?

c) How does a fuse wire protect electrical appliances?

15. a) What are the advantages of LED TV over the normal TV?

b) List the merits of LED bulb

16. What are the factors that affect the speed of sound in gases?

17. a) What do you understand by the term „ultrasonic vibration‟?

b) State three uses of ultrasonic vibrations.

c) Name three animals which can hear ultrasonic vibrations.

18. a) What is an echo?

b) State two conditions necessary for hearing an echo.

c) What are the medical applications of echo?

19. Compare the properties of alpha, beta and gamma radiations.

20. What is a nuclear reactor? Explain its essential parts with their functions.