Class 11th

The radii of circular orbits of two satellites A and B of the earth, are 4R and R, respectively. If speed of satellite A is 2V, then the speed of satellite B will be

A body of mass M is rotating in a vertical circle of radius r with critical speed. The difference in its kinetic energy at the top and the bottom is

Two trains 101 m and 99 m in length are running in opposite direction with velocities 54 km/h and 36 km/h. In what time they will completely cross each other?

The Boolean equation for the circuit as shown in figure is

 

When light of maximum wavelength 300 nm falls on a photoelectric emitter, photoelectrons are liberated. For another emitter however light of maximum wavelength 600 nm causes photoelectric emission. The ratio of work functions of first emitter to second emitter will be

The fringe width in Young's double slit experiment increases when

A heavy rope is suspended from rigid support. A wave pulse is set up at the lower end. Then

An object on a spring vibrates in a simple harmonic motion at a frequency of 4 hertz and an amplitude of 8 cm. If the mass of the object is 200 g, the spring constant is

The root mean square speed of molecules of a gas is 1260 m/s. The average speed of the gas molecules is

An ideal engine whose efficiency is 40%, receives heat at 500 K. If required efficiency is 50%, then intake temperature for the same exhaust temperature is