Question

The concentration of resistances is divided into two groups as follows.

Group-$1$	Group-$2$
The resistances are connected in series such that same(equal) electric current flows through each resistance.	The resistances are connected in parallel. So that the voltage drop through each resistance is same.
Equivalent resistance is more than every resistance connected in series.	Equivalent resistance is smaller than every resistance connected in parallel.

Which of the following is not true?

• A. The use of group-$2$ connection is to increase the resistance of circuit
• B. If we connect group-$2$, the equivalent resistance obtained is, $\frac{1}{R}=\frac{1}{R_1}+\frac{1}{R_2}+....+\frac{1}{R_n}$
• C. The use of group-$1$ connection is to increase the resistance of the circuit
• D. The use of group-$1$ connection is to decrease the resistance of the circuit

Answer 1

Answer: (A), (D)

The correct options are
A The use of group-$2$ connection is to increase the resistance of circuit
D The use of group-$1$ connection is to decrease the resistance of the circuit

In a parallel connection, the equivalent resistance of the circuit is smaller than the smallest resistance. Hence, it is used to reduce the resistance of the circuit.
In a series connection, the equivalent resistance of the circuit is greater than the largest resistance.

So, A and D are not true.