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 100o C is passed into 20 g of water at 10o C. When the water acquires a temperature of 80o C, the mass of water present will be,
24 g
31.5 g
42.5 g
42.5 g
D.
42.5 g
Heat lost by the steam = heat gained by water
Let, m' be the amount of heat converted into water.
m' x L = ms
m' x 540 = 20 x 1 x (80 - 10)
m' =
Therefore, net amount of water = 20 + 2.5 = 22.5 g
Certain quantity of water cools from 70o C to 60o C in the first 5 min and to 54o C in the next 5 min. The temperature of the surroundings is,
45o C
20o C
42o C
42o 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:
po Vo
2 po Vo
zero
The mean free path of molecules of a gas, (radius r) is inversely proportional to,
r3
r2
r
r