Current Electri...

Express which of the following setups can be used to verify Ohm's law :-

Figure $$(a)$$ below shows a Wheatstone bridge in which $$P, Q, R, S$$ are fixed resistances, $$G$$ is a galvanometer and $$B$$ is a battery. For this particular case the galvanometer shows zero deflection. Now, only the positions of $$B$$ and $$G$$ are interchanged,. as shown in figure $$(b)$$. The new deflection of the galvanometer.

In the circuits shown below the ammeter $$A$$ reads $$4   amp$$ and the voltmeter $$V$$ reads $$20  volts$$. The value of the resistance $$R$$ is

How many electrons constitute current of one micro ampere in one second?

Figure below shows a portion of an electric circuit with the currents in ampreres and their directions. The magnitude and direction of the current in the portion PQ is :

In the following circuit, each resistor has a resistance of $$15 \Omega$$ and the battery has an e.m.f. of $$12 V$$ with negligible internal resistance.
When a resistor of resistance $$R$$ is connected between $$D \& F$$, no current flows through the galvanometer (not shown in the figure) connected between $$C \& F$$. Calculate the value of $$R$$.

What is the minimum resistance that one can obtain by connecting all the five resistances each of $$0.5\Omega$$?

What is the effective resistance between points P and Q?

An electric iron draws a current of 15 A from a 220 V supply, What is the cost of using iron for 30 min everyday for 15 days if the cost of unit (1 unit =1 kWhr) is 2 rupees ? 

The value of equivalent resistance between the points $$A\;and\;B$$ in the given circuit, will be