Why is it that in a tangent galvanometer the aluminium pointer is fixed perpendicular to the magnetic needle and not parallel? Anyways , why is the aluminium pointer used after all cant we just measure the current by the defletion of the needle ? There is a statement that says "In a stationary wave all the particles in one loop are in the same phase while particles in the succeding loop are in opposite phase? " Can anyone explain ?? why is it that in deriving the expression for pressure exerted by a gas by the kinetic theory , we dont consider the gas molecule making collisions with any other molecule while colliding with the walls of the container back and forth ? If a solid conducting mass is moved in a uniform magnetic field, with the field always perpendicular to the plane of the conductor then is emf induced considering there is no change of flux thru the conductor. A Simple question to think about : If a hydrogen baloon is tied to the seat of a car moving in a circular path then what will be the direction of the balooon when windows are closed. ie will it move 1) inwards toward the centre, 2) Outwards , 3) Remain vertical.