A mental wire is stretched by suspending weight to if x is the longitudinal strain and y is young s modulus of elasticity then the elastic potential energy per unit volume is
Two point charge +3μC and +8μC repel each other with a force of 40 N if a charge of -5μC us added to each of them then the force between them will become
A two-slit arrangement is set up to produce an interference pattern on a screen. The fringes are too close together for convenient observation. How could the distance between them be increased?
Five equal forces of 10N each are applied at one point and all are lying in one plane.If the angles between them are equal,the resultant force will be:
A lift is moving downwards at a very high constant speed. A passenger present inside the lift standing on a weighing machine would notice that his weight
If a charged spherical conductor of radius 10 cm has potential V at a point distance 5 cm from its centre,then the potential at a point distance 15 cm from the centre will be
The percentage errors in the measurements of mass and speed are 2% and 3% respectively.How much will be the maximum error in the estimate of the kinetic energy obtained by measuring mass and speed.
The excess (equal in number) of electrons that must be placed on each of two small spheres spaced 3 cm apart,with force of repulsion between the spheres to be 10-19 N,is
Spherical balls of radius 'r' are falling in a viscous fluid of viscosity 'η' with a velocity 'v'. The retarding viscous force acting on the spherical ball is
A listener observes the frequency “f” of stationary source. If it move toward with 3
times of velocity of sound. Then the apparent frequency of the sound will be
The object is placed at the principle focus of a simple microscope if the focal length of the lens is 2cm what is the magnifying power of the microscope
A metal ball hangs from a spring balance which is placed on the wall of an elevator under freefall. Why does the spring balance show a weight of o(zero)N?
