Question 1 :
Various materials which are obtained from nature are called natural resources. Which of the following is not a natural resource?
Question 4 :
What are the advantages of using CNG and LPG as fuels?
Question 5 :
State True or False .The process of separating the various constituents of petroleum is known as refining.
Question 6 :
Which of the following is a pair of exhaustible natural resources?
Question 9 :
State True or False. The disadvantage of natural gas is that it can not be used directly for burning in homes.
Question 11 :
State True or False .Excessive burning of fossil fuels is a major cause of air pollution .
Question 12 :
Air is a natural resource and cannot be exhausted by human activities. It is known as inexhaustible natural resource. Which of the following is another inexhaustible natural resource?
Question 17 :
Fill in the blanks: The size of the pupil becomes__________ when you see in dim light.
Question 19 :
The distance between the object and its image formed by a plane mirror appears to be 24 cm. What is the distance between the mirror and the object?
Question 20 :
An interesting feature of a kaleidoscope is that you will never see the same pattern again. Is it TRUE OR FALSE?
Question 21 :
In the iris, there is a small opening called the __________?
Question 22 :
Mention whether regular or diffused reflection will take place when a beam of light strikes on a Piece of paper?
Question 23 :
How many images of a candle will be formed if it is placed between two parallel plane mirrors separated by 40 cm?
Question 25 :
An image formed by a mirror the left of the object appears on the right and the right appears on the left. This is known as _______________ ?
Question 26 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0faf59b460d7261f3a0.PNG' />
Refer to the above figure. Boojho stands at A just on the side of a plane mirror as shown in figure. Can he see the image of objects situated at P, Q and R?
Question 27 :
Which of the following statements is correct regarding rods and
cones in the human eye?
Question 28 :
The angle between the normal and incident ray is called the ___________ ?
Question 29 :
A person 1 m in front of a plane mirror seems to be _______ m away from his image.
Question 30 :
Choose the correct option, Image formed by a plane mirror is?
Question 36 :
Boojho saw a cracker burst at night at a distance from his house. He heard the sound of the cracker a little later after seeing the cracker burst. Give reason for the delay in hearing the sound.
Question 37 :
A pendulum oscillates 40 times in 4 seconds. Find its frequency.
Question 38 :
A list of mediums is given. (i) wood (ii) water (iii) air (iv) vacuum. In which of these mediums can sound travel?
Question 39 :
An object is vibrating at 50 hertz. What is its time period?
