A current carrying wire kept in a uniform magnetic field, will experience a maximum force when it is

The voltage across a resistor, an inductor, and a capacitor connected in series to an ac source are 20 V, 15 V and 30 V respectively. The resultant voltage in the circuit is

In a dc circuit the direction of current inside the battery and outside the battery respectively are -

The magnitude of electric field due to a point charge 2q, at distance r is E. Then the magnitude of electric field due to a uniformly charged thin spherical shell of radius R with total charge q at a distance $${r \over 2}(r > > R)$$ will be