Answer:
In order to improve visibility
Explanation:
Infrared telescopes are made using infrared cameras that contain infrared detectors which are solid-state and are maintained at very cold (cryogenic) temperatures
Infrared radiation is absorbed by water vapor which is present in the Earth's atmosphere, leading to the limitation of the use of infra red telescopes at high altitudes such as mountains, high flying planes or satellites
Answer : False.
Explanation : Acid rain is the indirect result of burning fossil fuels. As the incomplete combustion of fossil fuels releases sulfur dioxide and nitrous dioxide in the air. When it rains it gets mixed with water and forms nitric acid and sulfuric acid which causes acid rain. Acid rain is harmful.
Answer:
Number of turns on the secondary coil of the adapter transformer is 10.
Explanation:
For a transformer,

where
is the voltage induced in the secondary coil
is the voltage in the primary coil
is the number of turns of secondary coil
is the number of turns of primary coil
From the given question,
= 
⇒
= 
= 9.999733
∴
= 10 turns
Answer:
A) Cold object will start getting hot
B) Heat exchange will stop as the two object acquire the same temperature.
Explanation:
A) When one hot object and one cold object are kept in contact then the heat is transferred from the hot object to the cold object via different modes of heat transmission. Hence, the cold object starts getting hot
B) The transmission of heat from the hot object to the cold object will stop as the temperature of the two object becomes equal to each other.
Answer:

Explanation:
Given that,
Radius of a spherical shell, r = 0.7 m
Torque acting on the shell, 
Angular acceleration of the shell, 
We need to find the rotational inertia of the shell about the axis of rotation. The relation between the torque and the angular acceleration is given by :

I is the rotational inertia of the shell

So, the rotational inertia of the shell is
.