To forward-bias a diode, its p-type is to be connected to the positive terminal of a cell and n-type to the negative terminal of the cell. Is it necessary?

To reverse -bias a diode, its p-type is to be connected to the negative terminal of a cell and n-type to the positive terminal cell. Is it necessary?

The terminal Pd of a cell is equal to its emf if

One end each of resistance, capacitor C and resistance 2r are connected together. The other ends are respectively connected to the positive terminals of batteries. P, Q. R having respectively emf's E, E and 2E. The negative terminals of the batteries are then connected together. In this circuit, with steady current the potential drop across the capacitor is

___________ spot is seen on the potato around Wire connected to the positive terminal of battery.

If a battery is connected across a p-n junction with p-type connected to the negative terminal, the junction is said to be

A cell of emf 10 V and internal resistance 3 Omega is connected in parallel with another cell of emf 7V and internal resistance 3/5 Omega, such that their positive terminals are joined together and so there are negative terminals. Their positive terminals are joined with the negative terminal and their negative terminal is joined with the positive terminal of a third cell of emf 20 V with internal resistance 2Omega. The combination can be replaced by a battery of emf E and internal resistance r, then the values of E and R are respectively