Prove that the angle between the surface of an inclined plane and a the horizontal (the angle of inclination) is equal to the angle between the normal of the plane and the vertical.

Prove that the angle between the surface of an inclined plane and a the horizontal (the angle of inclination) is equal to the angle between the normal of the plane and the vertical.

The angle between the surface of an inclined plane and a the horizontal (the angle of inclination) is equal to the angle between the normal of the plane and the vertical.

Two charges of equal magnitude q are placed in air at a distance 2 a apart and third charge -2q is placed at mid – point. The potential energy of a system is? ( ԑo = permittivity of free space ) . (MHT-CET ~ 2014)

Two charges of equal magnitude q are placed in air at a distance 2 a apart and third charge -2q is placed at mid – point. The potential energy of a system is? ( ԑ_o = permittivity of free space ) . (MHT-CET ~ 2014)

a ] - q ² / ( 8 π ε _o a )                        b] - 3 q ² / ( 8 π ε _o a )                     

c] – 5 q ² / ( 8 π ε _o a )                     d] - 7 q ² / ( 8 π ε _o a )