Figure shows a small object M of length 1mm which lies along a dimentrical line of a glass sphere of radius 1-

A spherical hollow cavity is made in a lead sphere of radius R such that is surface touches the outside surface of the lead sphere and passes through its centre. The mass of the sphere before hollowing was M with what gravitational force will the hollowed out lead sphere attract a small sphere of mass m which lies at a distacne d from the centre of the lead sphere on the straight line connecting the centeres of the spheres and that of the hollow if d =2R .

A glass sphere of radius 15 cm has a small bubble 6 cm from its centre. The bubble is viewed along a diameter of the sphere from the side on which it lies. How for from the surface will it appear to be if the refractive index of glass is 1.5 ?

The distance between the circular plates of a parallel plate condenser 40 mm in diameter, in order to have same capacity as a sphere of radius 1 m is

Figure shows a shperical concave mirror of focal length f=5cm with its pole at (0,0) and principal axis along x-axis. There is a point object at (-40cm, 1cm), find the postion of image.

Figure shows two uniform rods of mass M and length l placed on two perpendicular lines. A small point mass m is placed on the point of intersection of the two lines. Find the net gravitational force experienced by m.

Electric charges are distributed in a small volume.The flux of the electric field through a spherical surface of radius 1 m surrounding the total charge is 100V -m .The flux over the concentric sphere of radius 2 m will be: