The figure shows a P-V diagram. How does the work done in the process change with time?
First decreases and then increases
First increases and then decreases
Continuously decreases
Continuously increases
A siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s. Frequency of sound to be heard by the listener is (velocity of sound = 330 m/s).
286.5 Hz
481.2 Hz
733.3 Hz
644.8 Hz
A wire fixed at the upper end stretches by length by applying a force F. The work done in stretching is
FΔl
2 FΔl
The Young's modulus of a wire is numerically equal to the stress which will
not change the length of the wire
double the length of the wire
increase the length
change the radius of the wire to half
According to Newton's law of cooling, the rate of cooling of a body is proportional to ()n 1, where Δθ is the difference of the temperature of the body and the surroundings and n is equal to
2
3
4
1
D.
1
According to Newton's law of cooling
∴ n = 1
Which of the following parameters does not characterize the thermodynamic state of matter?
Volume
Temperature
Pressure
Work
Point charges + 4q, - q and+ 4q are kept on the x-axis at points x = 0, x = a and x = 2a respectively, then
only- q is in stable equilibrium
all the charges are in stable equilibrium
all the charges are in unstable equilibrium
none of the above
If Ea be the electric field strength of a short dipole at a point on its axial line and Ee that on equilateral line at the same distance, then
Ee = 2Ea
Ea = 2Ee
Ea = Ee
none of these
If emf E = 4 cos 1000t volt is applied to an L-R circuit of inductance 3 mH and resistance 4 Ω, the amplitude of the current in the circuit is
1.0 A
0.8 A