A sample contains 16 gm of a radioactive material, the half life of which is two days. After 32 days, the amount of radioactive material left in the sample is
A step up transformer has transformation ratio of 3:2. What is the voltage in secondary if voltage in primary is 30 V
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A 500 kg car takes a round turn of radius 50 m with a velocity of 36 km/hr. The centripetal force is
The relation F = Ma, can not be deduced from Newton's second law if
What is the de Broglie wavelength (in Å) of the alpha- particle accelerated through a potential difference V ?
A transistor is operated in CB mode. If the collector base voltage is reduced to zero keeping the input current undisturbed, the output current will be:
Two trolleys of masses m and 3m are connected by a spring. They are compressed and released once. They move off in opposite directions and come to rest after covering distances S1 and S2 respectively. Assuming coefficient of friction uniform, the ratio of the distances S1 : S2 is
The number of turs of primary and secondary coils of a transformer are 5 and 10 respectively and mutual inductance of the transformer is 25 H. Now, number of turns in primary and secondary are made 10 and 5 respectuvely. Mutual inductance of transformer will be
In a gravitational field, work done in transporting a mass from one point to another depends only upon
When a glass rod is rubbed with silk, both become charged due to
The root mean swuare velocity of the gas molecules is ν at 300 K. The temperature, at which the root mean square velocity becomes double, is
The radiant energy from the sun incident normally at the surface of earth is 20 kcal/m2 min. What would have been the radiant energy incident normally on the earth, if the sun had a temperature twice of the present one
Two ions having equal masses but charges in the ratio 1:2 are projected perpendicular to a uniform magnetic field with speeds in the ratio 2:3. The ratio of the radii of the circular paths along which the two ions move is
The magnetic materials having negative magnetic susceptibility are
A plane is inclined at an angle θ with horizontal. A body of mass m rests on it. If the coefficient of friction is μ, then the minimum force that has to be applied parallel to the inclined plane to make the body just move up in the inclined plane is
The viscous drag on a spherical body moving with a speed ν in a viscous medium is directly proportional to
A motor car moving with a uniform speed of 20 m/sec comes to stop on the application of brakes after travelling a distance of 10 m. Its acceleration is
A 3 kg ball strikes a heavy rigid wall with a speed of 10 m/s at an angle of 60º .It gets reflected with the same speed and angle as shown .If the ball is in contact with the wall for 0.20 s, what is the average force exerted on the ball by the wall ?
If a ring is suspended from a point on a 2.25 m long string, then time period of oscillation will be(take g = 9.8 m-s⁻2)
Two points particles with masses m₁ and m₂ are thrown at angles θ₁ and θ₂ with the horizontal with speed ν₁ and ν₂ respectively. T,H and R represent the total time of flight, the maximum height attained and the horizontal range covered respectively. If ν₁ sin θ₁ = ν₂ sin θ₂, then for both the paricles
The velocity of a particle at which its mass is double its rest mass (where c is velocity of light), is
Light is incident on a glass plate at an angle of 60º. If reflected and refracted rays are mutually perpendicular, then refractive index of the glass plate is
A very small particle rests on the top of a hemisphere of radius 20 cm. The smallest horizontal velocity to be given to it if it is to leave the hemisphere without sliding down its surface
A boat is moving with a velocity 3î+4ĵ with respect to the ground. The water in the river is flowing with a velocity -3î-4ĵ with respect to the ground. The velocity of the boat relative to the water is
The internal resistance of a primary cell is 4 ohm. It generates a current of 0.2 amp in an external resistance of 21 ohm. The rate at which chemical energy is consumed in providing the current is
The value of surface tension of a liquid at critical temperature is
The densities of a liquid at 0º C and 100º C are respectively 1.0127 and 1. A specific gravity bottle is filled with 300 gm of the liquid at 0º C upto the brim and it is heated 100º C . Then the mass of the liquid expelled in grams is [Coefficient of linear expansion of glass = 9º 10 − 6 ∕ ºC ]
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1 videos|1 docs|68 tests
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