class 7 Physics final term examination-2023

 

Final term examination 2023

Subject: physics

Class 7 

Time allowed: 2 hours

Full marks: 80

Section-A(40 marks) 

all questions are compulsory

Q1. Select the correct alternative: [1×15=15 marks]

1.1 electricity does not flow through

A. Silver

B. Animals body

C. Rubber

D. Human body

1.2 the purpose of armature in an electric bell is

A. To provide spring action

B. To produce sound

C. To make and break the circuit

D. To produce magnetic field

1.3 volume of 1 ml is equal to

A.10-⁴ m³

B.10-⁵m³

C.10-⁶m³

D. 10-³cm³

1.4 the density of Aluminium is 2.7g/cm³ and of brass is 8.4g/cm³. For the same mass, the volume of:

A. Aluminium will be more than that of brass.

B. Aluminium will be less than that of brass.

C. Both will be same.

D. Nothing can be said.

1 .5 a ball falls down vertically. It's motion is:

A. Vibratory

B. Periodic

C. Circular

D. Linear

1.6 the earth attracts a body of mass 2 kg with a force of 20 Newton. The mass of a boy is 50 kg. His weight will be:

A. 500 Newton

B. 50 Newton

C. 5 Newton

D. None of these.

1.7 according to law of conservation of energy, energy changes from one form to another, but the total energy of that system

A. Remains the same

B. Increases

C. Decreases

D. Alternates

1.8 when rub our hands

A. Kinetic energy changes into potential energy

B. Potential energy changes into kinetic energy

C. Mechanical energy changes into heat energy.

D. Kinetic energy changes into potential energy and heat energy.

1.9 the angle between the incident ray and the plane mirror is 70 degree. The angle of incidence will be:

A. 70°

B. 20 degree

C. 35 degree

D. 90 degree

1.10the property due to which a light re striking a surface is written back into the same medium is called

A.Refraction

B. Reflection

C. Reflex action

D. None of these.

1.11 the minimum temperature which can be measured by a thermometer is (as per physics textbook of class 7 prescribed for the session 2022-23)

A. Zero degree celsius

B. 37 degree Celsius

C. 35 degree celsius

D. None of these.

1.12 the vacuum kept in between the walls of a thermos flas reduces, the heat transfer by:

A. Convection only

B. Conduction only

C. Conduction and convection

D. Radiation, conduction and convection.

1.13 the speed of sound in water is:

A. 332 m/s

B. 150 m/s

C .5000m/s

D 1.5 × 10⁵ cm/s

1.14 the minimum distance required between the source and the reflector so as to hear the echo in air is:

A. 16 m

B. 17 m

C. 34 m

D. 10 m

1.15 brass expands ......... More than iron.

A. One times

B. Two times.

C.1.5 times.

D. 2.5 times.

Q2. Film the  blanks:.  [1×5=5 ]

2.1 the strength of magnetic field of an electromagnet is......... By inserting a core of iron.

2.2 an ......... Is used to separate large mass of iron scrap.

2.3 in ......... Current flows due to the motion of ions.

2.4 the number of times a body vibrates in 1 second is called its..........m

2.5 ........... Doesn't require a medium for propagation.

Q3. Write true or false for each statement. Correct the first statement and rewrite it.   [1×10=10 marks]

3.1 a ticking clock sound is heard late when heard through a metal.

3.2 a male voice is shriller than the female voice.

3.3 sound cannot be produced by a vibrating bodies.

3.4 an infant can hear sound up to 35000 Hertz.

3.5 markari thermometer does makes use of the property of expansion of liquids on heating.

3.6 black surfaces are poor absorbers of heat radiations.

3.7 heat flows from a body at a low temperature to a body at high temperature when they are kept in contact.

3.8 the image formed by a plane mirror cannot be obtained on a screen.

3.9 the speed of light in water is 2.25 × 10⁸ ms-¹.

3.10 mass has both magnitude and direction.

Q4. Distinguish between following: [ 2×5=10 ]

4.1 rotatory motion and translatory motion.

4.2 parallel circuit and series circuit.

4.3 ultrasonic and infrasonic sound.

4.4 conduction and convection.

4.5 primary colours and secondary colours.

Section- B (40 marks)

Attempt any four questions

Each question carries 10 marks. ( 1+2+3+4=10)

Q5.1 define circuit.

5.2 state two precautions that you must take when switching on an electric circuit.

5.3 write three ways of increasing the magnetic field of an electromagnet.

5.4 what is a dry cell. Draw a well label diagram of a dry cell. Write four advantages of dry cells.

Q6.1 what do you mean by reflection of sound?

6.2 explain how you can predict the arrival of a train by placing your year on the rails without seeing it.

6.3 what are land and sea breezes? Explain there formation with help of suitable diagram.

6.4 write four uses of a plane mirror.

Q7.1 what do you mean by a lateral inversion?

7.2 define potential energy and explain the factors on which it depends.

7.3 what is a thermometer? Draw a well labelled diagram of a thermometer.

7.4 write four differences between mass and weight.

Q8.1 why mercury is used in a barometer to measure the atmospheric pressure?

8.2 established a relationship between SI and CGS unit of density with help of suitable mathematical calculations.

8.3 draw a diagram to show formation of image of finite size object by a plane mirror.

8.4 a man keeps A ball of mass 500 gram at a height of 10 m. If ball falls on the ground then,what would be the velocity of the ball just before hitting on the ground? Take acceleration due to gravity= 10m/s². State the assumption if any.

Q9.1 a truck travels with speed 40 km/h for 30 minutes and then with speed 62 km per hour for 1 hour.find:

A. Total distance travelled by the truck.

B. Average speed of truck

9.2 how long a train will take to travel a distance of 400 km with speed of 60 km per hour?

9.3 the angle of incidence on the plane mirror is 30 degree. Draw the ray diagram and then find angle formed between the incident ray and the reflected ray.

9.4 convert the following:

A. Convert normal human body temperature 98.6 degree fahrenheit into degree celsius.

B. Convert the temperature of water at 30 degree Celsius to degree fahrenheit.