11.

Dependence of intensity of gravitational field (E) of earth with distance (r) from centre of earth is correctly represented by,

• 

• 

• 

• 

Two cities are 150 km apart. electric power is sent from one city to another city through copper wires. The fall of potential per km is 8 V and the average resistance per km is 8 V and the average resistance per km is . The power loss in the wire is,

• 19.2 W

• 19.2 kW

• 19.2 J

• 12.2 kW

The oscillation of a body on a smooth horizontal surface is represented by the equation, X = A cos (t)
where, X is the displacement at time t

 is the frequency of the oscillation
Which one of the following graphs shows correctly the variation of a with t?

Copper of fixed volume V is drawn into wire of length l. When this wire is subjected to a constant force F, the extension produced in the wire is . Which of the following graphs is a straight line?

A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then

• Energy = 4VT  is released.

• Energy = 3VT is absorbed

• Energy = 3 VT  is released

• Energy is neither absorbed nor released.

Steam at 100^o C is passed into 20 g of water at 10^o C. When the water acquires a temperature of 80^o C, the mass of water present will be,

• 24 g

• 31.5 g

• 42.5 g

• 42.5 g

Certain quantity of water cools from 70^o C to 60^o C in the first 5 min and to 54^o  C in the next 5 min. The temperature of the surroundings is,

• 45^o C

• 20^o C

• 42^o C

• 42^o C

A monoatomic gas at a pressure p, having a volume V expands isothermally to a volume 16 V. The final pressure of the is (take ),

• 64 p

• 32 p

• 
• 

A thermodynamic system undergoes cyclic process ABCDA as shown in the figure. The work done by the system in the cycle is:

• p_o V_o

• 2 p_o V_o

• 

• zero

The mean free path of molecules of a gas, (radius r) is inversely proportional to,

• r³

• r²

• r

• r