Which of the following circuits represents a full-wave rectifier?

If a centre-tap transformer is used with two $p-n$ junction diodes for full-wave rectification,then the output voltage of the rectifier with respect to each diode is (secondary voltage of transformer $= V_s$)

In the circuit shown,the average power dissipated in the resistor is (assume diode to be ideal).

When $p$-type and $n$-type semiconductors are brought into contact,they form a $P-N$ junction which acts as a .........

If in a $p-n$ junction,a sinusoidal input signal is applied at $A$ as shown,then the output voltage $V_0$ will be:

$A$ diode detector is used to detect an amplitude modulated wave of $60\%$ modulation by using a condenser of capacity $250\, pF$ in parallel with a load resistance $100\, k\Omega$. Find the maximum modulated frequency which could be detected by it.