When a ship enters the sea from a river, it rises a little since salt water is denser than river water. As the density of river water is less than that of the sea water, the water displaced by the ship in the river is more than that displaced in the sea. So it rises as it enters sea from river.

Correct Option: C

When a ship enters the sea from a river, it rises a little since salt water is denser than river water. As the density of river water is less than that of the sea water, the water displaced by the ship in the river is more than that displaced in the sea. So it rises as it enters sea from river.

Weight of a body is the force with which it is attracted towards the centre of earth. The weight of a body, ‘w’ of mass ‘m’ is given by: W = mg, where ‘g’ is the acceleration due to gravity At the centre of earth, value of ‘g’ is zero. Therefore, weight of a body is zero at the centre of the earth.

Correct Option: B

Weight of a body is the force with which it is attracted towards the centre of earth. The weight of a body, ‘w’ of mass ‘m’ is given by: W = mg, where ‘g’ is the acceleration due to gravity At the centre of earth, value of ‘g’ is zero. Therefore, weight of a body is zero at the centre of the earth.

Using Kepler’s Third Law,

	T2	=		R		3
	T12			4R

Correct Option: A

Using Kepler’s Third Law,

	T2	=		R		3
	T12			4R

According to Newton’s law of cooling, the rate of loss of heat of a body is directly proportional to the difference between the temperature of hot body and temperature of the surroundings, provided that the difference in temperature is small enough.

Correct Option: B

According to Newton’s law of cooling, the rate of loss of heat of a body is directly proportional to the difference between the temperature of hot body and temperature of the surroundings, provided that the difference in temperature is small enough.

When a non-relativistic electron and a non-relativistic proton are moving and have the same de Broglie wavelength, then they will have the same linear momentum p = mv. If the electron and proton have the same momentum, they cannot have the same speed because of the difference in their masses. An electron and photon can have the same wavelength since the wavelength of electron can be changed by changing its velocity.

Correct Option: B

When a non-relativistic electron and a non-relativistic proton are moving and have the same de Broglie wavelength, then they will have the same linear momentum p = mv. If the electron and proton have the same momentum, they cannot have the same speed because of the difference in their masses. An electron and photon can have the same wavelength since the wavelength of electron can be changed by changing its velocity.