A wire elongates by l mm when a load W is hanged from it. If the wire goes over
A wire elongates by l mm when a load W is hanged from it. If the wire goes over a pulley and two weights W each are hung at the two ends, the elongation of […]
Questions
A bimetallic strip consists of metals X and Y. It is mounted rigidly at the base as shown
A bimetallic strip consists of metals X and Y. It is mounted rigidly at the base as shown. The metal X has a higher coefficient of expansion compared to that for metal Y. When the […]
A polished metal plate has a rough and black-spot. It is heated to 1400 K
A polished metal plate has a rough and black-spot. It is heated to 1400 K and brought immediately in dark room. Then
Options
(a) The spot will appear darker than the plate (b) The […]
A pan is suspended from a steel wire. Weights are slowly put on the pan
A pan is suspended from a steel wire. Weights are slowly put on the pan and as the weight increases, the change in the length of the steel wire
Options
(a) Will be uniform […]
If a small sphere is let fall vertically in a large quantity of still liquid of density
If a small sphere is let fall vertically in a large quantity of still liquid of density smaller than that of the material of the sphere
Options
(a) At first its velocity increases, but […]
The surface temperature of the sun which has maximum energy
The surface temperature of the sun which has maximum energy emission at 500 nm is 6000 K. The temperature of a star which has maximum energy emission at 400 nm will be
Options
(a) […]
A body is under stress F and has Young’s modulus Y, then the energy
A body is under stress F and has Young’s modulus Y, then the energy stored per unit volume equals to
Options
(a) F²/2Y (b) Y/2F² (c) 2Y/F² (d) 2F²/Y
Correct Answer:
F²/2Y
Explanation:
Energy […]
If a spring of spring constant k stretched by a length x under tension T, the energy
If a spring of spring constant k stretched by a length x under tension T, the energy stored is
Options
(a) 2k/T² (b) 2T²/k (c) T²/2k (d) 2T/k²
Correct Answer:
T²/2k
Explanation:
Energy stored […]
Three objects coloured black, gray and white can withstand hostile conditions upto 2800⁰C.
Three objects coloured black, gray and white can withstand hostile conditions upto 2800⁰C. These objects are thrown into a furnace where each of them attains a temperature of 2000⁰C. Which object will glow brightest?
A body of mass 120 kg and density 600 kg/m³ floats in water.
A body of mass 120 kg and density 600 kg/m³ floats in water. What additional mass could be added to the body so that the body will just sink?
Options
(a) 20 kg (b) […]