The number of turns in the primary and the secondary turns of a transformer are 1000 and 3000 respectively. If 80 volts A.C. is supplied to the primary coil of the transformer, then the potential difference/turn of the secondary coil would be
Cathode rays are similar to visible light rays, in that
A series combination of R,L,C is connected to an a.c. source. If resistance is 3 Ω and the circuit is :
Power factor,
A tube of length L is filled completely with an incompressible liquid of mass M and closed at both the ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity ω. The force exerted by the liquid at the other end is
A shell initially at rest explodes into two pieces of equal mass. The two pieces will
A moving coil galvanometer has a resistance of 50 Ω and gives full scale deflection for 10 mA. How could it be converted into an ammeter with a full scale deflection for 1A?
Stress to Strain ratio is equivalent to
Photo cell is a device to
Consider the following statements regarding the magnitude of barrier potential of a PN junction:
1. It is independent of temperature
2. It depends on difference between fermi levels on two sides of junction.
3. It depends on forbidden energy gap on two types of semiconductors
4. It depends on impurity concentration in P and N type semiconductors
Which of the statements given above is/are correct?
If an unchanged capacitor is charged by connecting it to a battery, then the amount of energy lost as heat is
A motorcyclist of mass m is to negotiate a curve of radius r with a speed ν. The minimum value of the coefficient of friction so that this negotiation may take place safely, is
A satellite is revolving near the earth's surface. Its orbital velocity is
Heat travels through vacuum by
The factor not needed to calculate heat lost or gained when there is no change of state, is
A galvanometer of 100 Ω resistance gives full scale deflection with 0.01 A current. How much shunt resistance should be connected with it to convert into an ammeter of range 10 A?
A rocket of mass 6000 kg is fired from earth with speed 1 km/s. What should be the rate of ejection of gas, so that it moves with initial acceleration 20 m/s^{2}? (Take g = 10 m/s^{2})
ΔM/Δt
= rate of ejection of fuel
Acceleration of the rocket in the presence of grarity
In a container, the velocity of water flowing through a hole at a depth h from the surface of water is 5 ms⁻^{1}. If the container has the hole at a depth 4h from the surface of water, then velocity of water flowing through the hole is
A body falling from a high Minaret travels 40 metres in the last 2 seconds of its fall to ground. Height of Minaret in metres is (take g = 10m/s^{2})
The figure below shows the various positions (labelled by subscripts) of small magnetized needles P and Q. The arrows show the direction of their magnetic moment. Which configuration corresponds to the lowest potential energy among all the configurations shown?
A stone released with zero velocity from the top of the tower reaches the ground in 4 seconds. The height of the tower is about
Two simple pendulums of length 0.5 m and 20 m respectively are given small linear displacement in one direction at the same time. They will again be in the phase when the pendulum of shorter length has completed... oscillations
A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads 49 N, when the lift is stationary. If the lift moves downward with an acceleration of 5m/s^{2}, the reading of the spring balance will be
Max. height of a bullet when fired at 30^{°} with the horizontal is 11 m. Then height when it is fired at 60^{°} is
Two capillary tubes of same diameter are put vertically one each in two liquids whose relative densities are 0.8 and 0.6 and surface tension are 60 and 50 dynes/cm respectively. Ratio of heights of liquid in the two tubes, h₁ / h₂ is
Green light of wavelength 5460 Å is incident on an air glass interface. If refractive index of glass is 1.5, then wavelength of light in glass would be
A circular turn table has a block of ice placed at its centre. The system rotates with an angular speed ω about an axis passing through the centre of the table. If the ice melts on its own without any evaporation, the speed of rotation of the system
In an experiment of simple pendulum, the errors in the measurement of length of the pendulum (L) and time period (T) are 3%v and 2% respectively. The maximum percentage error in the values of (L/T^{2}) is
When a cylindrical tube is dipped vertically into a liquid, the angle of contact is 140°. When the tube is dipped with an inclination of 40°, then angle of contact is
The emf in a thermoelectric circuit with one junction at 0°C and the other at t°C is given by E = AtBt^{2}. The neutral temperature is then
A cylinder contained 10 kg of gas at 10^{7} N/m^{2}. The quantity of gas taken out of cylinder if final pressure is 2.5 x 10^{6} N ∕ m^{2} is (temp. is constant)
The mechanical equivalent of heat J is
For the equation F ∝ A^{a} V^{b} D^{c} , where F is the force, A is the area, V is the velocity and D is the density, the dimensional formula gives the following values
In Young's double slit experiment, the width of the fringes obtained with light of wavelength 6000 Angstrom is 2.0mm. The fringe width, if the entire apparatus is immersed in a liquid of refractive index 1.33, will be
Fringe width in Young's double slit experiment β = Dλ/d
When apparatus is immersed in liquid, only wavelength of light (λ) changes
Wavelength of light is liquid,
λ' = λ n , where n = refractive index of medium
Initial fringe width, β = Dλ/d .....(i)
Fringe width in liquid, β' = Dλ'/d .....(ii)
Dividing Equation (ii) by Equation (i), we get
β'/β = λ'/λ
The new fringe width, β' = 2.0/1.33 mm = 1.5 mm
A tuning fork whose frequency as given by manufacturer is 512 Hz is being tested with an accurate oscillator. It is found that the fork produces a beat of 2 Hz when oscillator reads 514 Hz but produces a beat of 6 Hz when oscillator reads 510 Hz. The actual frequency of fork is
A motor boat is having a steady speed of 20 ms^{1}. If the water resistance to the motor boat is 600 N, the power of the engine is
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