MEDIUM
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What is the main agent responsible for chemical weathering in rocks?

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Important Questions on Limits and Derivatives

EASY
A copper rod of 88 cm and an aluminum rod of unknown length have their increase in length independent of increase in temperature. The length of aluminum rod is αCu=1.7×10-5 K-1andαAl=2.2×10-5K-1 
MEDIUM
A rod, of length L at room temperature and uniform area of cross section A, is made of a metal having coefficient of linear expansion α /°C It is observed that an external compressive force F is applied on each of its ends, prevents any change in the length of the rod when its temperature rises by T K Young's modulus, Y for this metal is:
MEDIUM
An ideal gas is expanding such that PT= constant. The coefficient of volume expansion of the gas is
EASY
Two systems are in thermal equilibrium. The quantity which is common for them is
EASY
In an experiment, a sphere of aluminium of mass 0.20 kg is heated up to 150°C . Immediately, it is put into water of volume 150 cc at 27oC kept in a calorimeter of water equivalent to 0.025 kg . The final temperature of the system is 40oC . The specific heat of the aluminium is(take 4.2 Joule=1 calorie )
MEDIUM
If y=x+c1+x2 where c is a constant, when y is stationary, xy is equal to -
MEDIUM
It is hotter at the same distance over the top of a fire than it is on the side of it, mainly because :
EASY
Explain why felt rather than air is used for thermal insulation even though the thermal conductivity of air is less than that of felt?
EASY
An ordinary electric fan does not cool the air; still, it gives comfort in summer. Explain.
EASY
In which of the following process, convection does not takes place primarily?
MEDIUM
A liquid of mass m and specific heat c is heated to a temperature 2T. Another liquid of mass m2 and specific heat 2c is heated to a temperature T. If these two liquids are mixed, the resulting temperature of the mixture is
EASY

Assertion: It is hotter over the top of fire than at the same distance on the sides.

Reason: Air surrounding the fire conducts more heat upwards.

EASY
The equatorial and polar regions of the earth receive unequal solar heat. The convection current arising due to this is called: