A particle executes the simple harmonic motion with an amplitude ' $A$ '. The distance travelled by it in one periodic time is

A galvanometer has resistance of $100 \Omega$ and a current of 10 mA produces full scale deflection in it. The resistance to be connected in series, to get a voltmeter of range 50 volt is

The angle made by orbital angular momentum of electron with the direction of the orbital magnetic moment is

The circuit in 1$$\Omega$$ resistor in the following circuit is