SCIENCE
PHYSICS
MARKS: 16
CLASS: VII
Time: 45 minutes
1. In a simple pendulum, the metallic ball suspended by a thread is called its....Bob
...... 1
2. Give reason
a). In place of hot climate it is advised that the outer walls of house be painted white.
b). It is more comfortable to wear dark coloured clothes in winter.
2
3. Define speed. Salma takes 15 minutes her house to reach her school on a bicycle.
If the bicycle has a speed of 2 m/s, calculate the distance between her house and the
school.
2
4. Draw the distance time graph for the motion in the following cases.
a). A car moving with a constant speed.
b). A car parked on a side road.
c). A car moving with non uniform speed.
3
5. Explain different modes of transfer of heat.
3
6. (). State similarities and differences between the laboratory thermometer and the
clinical thermometer.
5
(ii). What precautions should we take while reading a clinical thermometer.
Answers
Answer:
kya hai ye btao bhai
Answer:
1. A simple pendulum consists of a small metallic ball or a piece of stone suspended from a rigid stand by a thread. The metallic ball is called the bob of the pendulum.
2. a) In places of hot climate it is advised that the outer wall of houses be painted white because white color reflects heat and the houses do not heat up too much.
b)We wear dark coloured clothes in winter to keep us warm as they absorb all the heat radiation coming from the sun whereas light coloured clothes reflect most of the heat radiation that falls on them and therefore we feel more comfortable wearing them in the summer.
3.
Given :
Speed of the bicycle= 2 m/s
Time taken by Salma to reach school from her house = 15 minutes = 15 × 60 s = 900 s
We know that speed = distance / time
Hence Distance = Speed × time
= 2 m/s × 900 sec
= 1800 m
=1.8 km
Distance between Salma's house and school =1.8 km
4.
(i) A bike moving with a constant speed:
(ii) A car parked on a road side:
5. MODES OF HEAT TRANSFER : There are three modes of heat transfer namely conduction, convection and radiation. Conduction : Conduction refers to the heat transfer that occurs across the medium. Medium can be solid or a fluid.Bulbs contain mercury.
Glass tubes are long, narrow and uniform.
6. Differences:
The clinical thermometer is used to measure body temperature, however, laboratory thermometer is not used for the purpose of measuring body temperature.
The temperature range of clinical thermometers is 35°C to 42°C and that of laboratory thermometers is -10°C to 110°C.
The least count of both the thermometers is different.
The clinical thermometer is can be tilted while reading the temperature values whereas laboratory thermometer need to be kept upright.