WINTER VACATIONS HOMEWORK

1. Complete your practical file. Write all the experiments of Physics and chemistry of Term II in your file.
2.Complete the assignments given in the class.
3. Prepare chapter 'Sound' and 'Work and Energy'

Very short answer type questions of chapter sound

ASSIGNMENT 2

1. Sound is considered as a mechanical wave. Give reason
2. Differentiate between
(a) wave and a pulse
(b) loudness and Intensity of sound
(c) a tone and a note
(d) Noise and Music
(e) Echo and Reverberation
3. Give a  relation between
(a) loudness and amplitude of a wave
(b) Intensity and Amplitude of a wave
(c) Time period and Frequency of a wave
(d) Velocity, wavelength and frequency of a wave
4. Ceilings of a concert halls are curved. Justify.
5(a). Name the unit in which Intensity of  a sound can be measured.
(b) Identify the characteritics on which loudness and Pitch of a sound depends.

ASSIGNMENT BASED ON CHAPTER SOUND

ASSIGNMENT --1

NUMERICALS
1.A person listening to a tone of 500 Hz sitting at a distance of 450m from the source of the sound.What is the  time between successive compressions from the source?(Given speed of sound in air =330m/s)
2. An echo returned in 3s. What is the distance of the reflecting surface from the source?(Given Speed of sound is 342m/s)
3. A ship sends out ultrasound that returns from the sea bed and it is detected  after 3.42s. If the speed of ultrasound through the sea water is 1531m/s, what is the distance of sea bed from the ship?
4. A person has a hearing range from 20 Hz to 20 KHz. What are the typical wavelengths of sound waves in air corresponding to these frequencies.(Given Speed of sound in air is 344m/s)
5. A submarine emits a SONAR pulse which returned from an underwater cliff in 1.02s. If the speed of sound in salt water is  1531m/s, how far away is the cliff?

characteristics of a sound wave

Students can revise the characteristics of a sound wave by watching this video.

PROJECT

Collect the electricity bills of your house for the months June to  November.
Make graphs b/w
(a) Month and Cost of the Bill
(b) Month and Units  Consumed

From the graph, infer about the month of max. bill and max. consumption.

List the possible reasons for the same. Also suggest the measures to conserve electricity so lower the bill.

Rubrics of evaluation:
Presentation:3 MARKS
COMPLETENESS:3 marks
Timely submission:2
Originality:2 marks

work done

Ch. Work and Energy
Work and its types
Energy
Derivation of expressions for Kinetic and Potential Energy
Statement and Proof of Law of Conservation of Energy

assignment from chapter MOTION

NUMERICALS

1. The velocity acquired by a body moving with uniform acceleration is 12 m/s in 2s and 18 m/s in 4 s. Find the initial velocity of the body.

2. A stone  is dropped freely in the river from a bridge. It takes 5 s to touch the water surface in tyhe river. Calculate
(a) the height of the bridge from the water level
(b) the distance covered by stone in the last second(g=9.8 m/s^2)
(Ans.(a) 122.5m   (b)44.1 m)

3. A body is dropped under gravity from the top of a tower of height 78.4 m. Calculate
(a) time to reach the ground
(b) velocity with which it will strike the ground.

4.  A body with an initial velocity of 18 km/h accelerates uniformly at the rate of 9cm/s^2 over a distance of 200 m. Calculate
(a) acceleration
(b) final velocity

5. A ball is thrown vertically upwards. It goes to a height of 19.6 m and then returns back to the ground. Find the
(a) initial velocity of the ball
(b) total time of journey
(c) final velocity of the ball when it strikes the ground.