Eight equal drops of water are falling through air with a steady velocity of 10 cm s-1. If the drops combine to form a single drop big in size, then the terminal velocity of this big drop is
40 cms-1
10 cms-1
30 cms-1
80 cms-1
Two capillary tubes of different diameters are dipped in water. The rise of water is
the same in both tubes
greater in the tube of larger diameter
greater in the tube of smaller diameter
independent of the diameter of the tube
A perfect gas at 27°C is heated at constant pressure so as to double its volume. The increase in temperature of the gas will be
600°C
327°C
54°C
300°C
Three identical rods A, B and C are placed end to end. A temperature difference is maintained between the free ends of A and C. The thermal conductivity of B is thrice that of C and half ofthat of A. The effective thermal conductivity of the system will be (KA is the thermal conductivity of rod A)
3 KA
2 KA
A.
Given, KB = KA/2
and KB = 3KC
∴ KC = KA/6
Rods are in series form so
The quantities of heat required to raise the temperatures of two copperspheres of radii r1 and r2 (r1 = 1.51 r2) through 1 K are in the ratio of
1
Which one of the following is v-T graph for perfectly black body ? vm is the frequency of radiation with maximum intensity. T is the absolute temperature.
A
B
C
D
A particle executing a simple harmonic motion has a period of 6 s. The time taken by the particle to move from the mean position to half the amplitude, starting from the mean position is
The equation of a wave is given by . If the displacement is 5 cm at t = 0, then the total phase at t =7.5 s is
Two tuning forks A and B, produce notes of frequencies 258 Hz and 262 Hz. An unknown note sounded with A produces certain beats. When the same note is sounded with B, the beat frequency gets doubled. The unknown frequency is
250 Hz
252 Hz
254 Hz
256 Hz
A wire under tension vibrates with a fundamental frequency of 600 Hz. If the length of the wire is doubled, the radius is halved and the wire is made to vibrate under one-ninth the tension. Then the fundamental frequency will become
200 Hz
300 Hz
600 Hz
400 Hz