Metal detector works on the principle of
If γ is the susceptibility and μr is the relative permeability of a ferromagnetic substance, then
It is found that a non-zero current is unable to produce any magnetic field at a particular point. Then the angle between the current element and the position vector of that point with respect to the current element is:
A wire of resistance 2R is stretched such that its length is doubled. Then the increase in its resistance is:
The effective capacitance between points A and B shown in the circuit is:
If the electrical potential at a point on the surface of a hollow conducting sphere of radius R is V, then the electric potential at a point which is at a distance R/3 from the centre of the sphere is:
A point source of light is placed at the focus of a concave mirror. Consider only paraxial rays. The shapes of the wavefronts of incident and reflected lights respectively are:
Two convex lenses of focal lengths 20 cm and 30 cm are placed in contact with each other co-axially. The focal length of the combination is:
A source and an observer move away from each other with same velocity of 10 m-1 with respect to the ground. If the observer finds the frequency of sound coming from the source as 1980 Hz, then the actual frequency of the source is (speed of sound in air = 340 ms-1)
Among the following statements, the correct statement for a wave is:
N molecules each of mass m of gas A and 2N molecules each of mass 2m of gas B are contained in a vessel which is maintained at a temperature T. The mean square velocity of the molecules of gas B is denoted by V22 and the mean square of the x-component velocity of the molecules of gas B is denoted by V12, then V1\V2 is:
The Fahrenheit and Kelvin scales of temperature will have the same reading at a temperature of:
A cylinder of mass m and material density ρ hanging from a string is lowered into a vessel of cross - sectional area A containing a liquid of density σ (< ρ) until it is fully immersed. The increase in pressure at the bottom of the vessel is:
A cylindrical vessel, open at the top, contains 15 liters of water. Water drains out through a small opening at the bottom. 5 liters of water comes out in time t1, the next 5 litre in further time t2, and the last 5 litre in further time t3. then:
The dimensions of four wires if the same material are given below. The increase in length is maximum in the wire of :
A man weighing 75 kg is standing in a lift. The weight of the man standing on a weighing machine kept in the lift when the lift is moving downwards freely under gravity is:
The displacement of a particle executing simple harmonic motion is given by x = 2cos(t) where t is the time in seconds then the time period of the particle is:
The ratio of the radii of two solid spheres of same mass in 2:3. The ratio of the moments of inertia of the spheres about their diameters is:
An engine is dragging a mass of 5000 kg with a velocity of 5 ms-1 along a smooth inclined plane of inclination 1 in 50. Then the power of the engine is
A player can throw a ball to a maximum horizontal distance of 80 m. If he throws the ball vertically with the same velocity, then the maximum height reached by the ball is:
The number of significant figures in the measurement of a length 0.079000 m is:
The perimeter of a △ABC is 6 times the arithmetic mean of the values of the sine of its angles. If the side BC is of the unit length, then ∠A =