A body takes T minutes to cool from 62 degree C to 61 degree C when the surrounding temperature is 30 degree C. The time taken by the body to cool from 46 degree C to 45.5 degree C is
A flywheel rotates with uniform angular acceleration. Its angular velocity increases from 20π rads−1 to 40 π rads−1 in 10 s. How many rotations did it make in this period?
A solid sphere roll down two different inclined planes of same height but of different inclinations. In both cases
Minimum no. of 8 μF and 250 V capacitors, used to make a combination of 16 μF and 1000 V, is
Which of the following statements is absolutely correct about mass?
The moment of inertia of a body about a given axis is 1.2 kg m2 . Initially, the body is at rest. In order to produce rotational kinetic energy of 1500 J , and angular acceleration of 25 rad s−2 must be applied about that axis for a duration of
A solid disc of mass M is just held in air horizontal by throwing 40 stones per sec vertically upwards to strike the disc each with a velocity 6 ms−1. If the mass of each stone is 0.05 kg 0.05 kg . What is the mass of the disc (g = 10 ms−2 )
The power factor of a series LCR circuit when at resonance is
Cathode rays are similar to visible light rays in that
A cyclic process is shown in the figure. Work done during the cyclic process
is

An ideal gas is heated from 27°C to 627°C at constant pressure. If initial volume was 4 m3, then the final volume of the gas will be
and
are joined with an ideal spring of spring constant
and kept on rough surface as shown. The spring is initially unstretched and the coefficient of friction between the blocks and the horizontal surface is
. What should be the maximum speed of the block of mass
such that the smaller block does not move?
The moment of inertia about an axis of a body which is rotating with angular velocity 1 rads−1 is numerically equal to
A fly wheel of radius R and of moment of inertia I can be rotated in vertical plane without friction about its natural axis. A light string is wound over the wheel and a body of weight W is suspended at the other end of string. The angular acceleration of wheel when suspended body is released is
A fireman of mass 60 kg slides down a pole. He is pressing the pole with a force of 600 N. The coefficient of friction between the hands and the pole is 0.5, with what acceleration will the fireman slide down (g=10m/s2)
One quarter of the disc of mass mis removed. If r be the radius of the disc, the new moment of inertia is
At any instant, a rolling body may be considered to be in pure rotation about an axis through the point of contact. This axis is translating forward with speed
Two bodies of masses
and
are placed at a distance
. The gravitational potential at a point on the line joining them, where gravitational field is zero, is (
is universal gravitational constant)
A spool is pulled horizontally by two equal and opposite forces as shown in Figure. Which of the following statements are correct?

and
are placed together to form a double convex lens. The final focal length will beA L shaped rod of mass M is free to rotate in a vertical plane about axis AA' as shown in figure. Maximum angular acceleration of rod is-

By increasing the temperature, the specific resistance of a conductor and a semiconductor
In LCR circuit, the capacitance is changed from C to 4C. For the same resonant frequency the inductance should be changed from L to
The radius of the first orbit of the hydrogen atom is a₀. The radius of the second orbit will be
If rigidity modulus is 2.6 times of youngs modulus then the value of poission's ratio is
1 videos|4 docs|90 tests |
1 videos|4 docs|90 tests |