Combination of Resistors

Q.

Derivation of formula of resistor connected in series and parallel

Q.

When $n$ resistors, each of resistance $R$, are connected in series, the equivalent resistance is ___. When $n$ resistors, each of resistance $R$, are connected in parallel, their equivalent resistance is ___.

1. $nR,nR$

2. $nR,\frac{R}{n}$

3. $\frac{R}{n},\frac{R}{n}$

4. $\frac{R}{n},nR$

Q.

What is the minimum resistance which can be made using five resistors each of $\frac{1}{5}\mathrm{\Omega }$?

1. $\frac{1}{5}\mathrm{\Omega }$

2. $\frac{1}{25}\mathrm{\Omega }$

3. $\frac{1}{10}\mathrm{\Omega }$

4. $25\mathrm{\Omega }$

Q.

What is the difference between loop and mesh?

Q.

Calculate the current flowing through each of the resistors A and B in the circuit shown in the figure.

Q.

Two resistors, with resistance $5\Omega$ and $10\Omega$ respectively are to be connected to a battery of emf 6 V so as to obtain:
(a) minimum current flowing
(b) maximum current flowing
(c) How will you connect the resistances in each case?
(d) Calculate the strength of the total current in the circuit in the two cases.

Q.

How do you think the brightness of two lamps arranged in parallel compares with the brightness of two lamps arranged in series (Both arrangements having one cell)?

Q.

In the circuit shown below:

The potential difference across the $3\Omega$ resistor is :
$\left(a\right)\frac{1}{9}V\left(b\right)\frac{1}{2}\left(c\right)1V\left(d\right)2V$

Q.

What happens to the other bulbes in a series circuit if one bulb blows off?

Q. Which bulb will glow brighter, a 40 Watt bulb or a 60 watt when connected in series. Why?

Q.

In the circuit diagram given below. Find



(i) Total resistance of the circuit

(ii) Total current flowing in the circuit

(iii) Potential difference across $R_1$

4. Define one ohm.

5. Define one ampere of current. [5 MARKS]

Q. What is the equivalent resistance between A and B in the circuit of figure if $R=3\Omega$.

1. $8\Omega$
2. $6\Omega$
3. $7\Omega$
4. $9\Omega$

Q.

A piece of wire of resistance $\mathrm{R}$ is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is $\mathrm{R}$, then the ratio $\frac{\mathrm{R}}{\mathrm{R}}$ is _____.

1. $\frac{1}{25}$

2. $\frac{1}{5}$

3. $5$

4. $25$

Q.

A cell of e.m.f. 2 V and internal resistance $1.2\Omega$ is connected to an ammeter of resistance $0.8\Omega$ and two resistors of $4.5\Omega$ and $9\Omega$ as shown in the figure.
Find:
(a) the reading of the ammeter,
(b) the potential difference across the terminals of the cell, and
(c) the potential difference across the $4.5\Omega$ resistor.

Q.

When n resistances each of value R are connected in parallel, then resultant resistance is x. When these n resistances are connected in series, total resistance is

1. nx

2. 

3. 

4. 

Q.

Find equivalent resistance between A & B in the circuit:

1. 8.5

2. 16.5

3. 49

4. 18

Q. Two resistors of 5 ohm and 10 ohm are connected in series in a circuit. How does the current passing through them compare

Q.

A series circuit has only one path for the current to flow through, whereas a parallel circuit has multiple paths.

1. False

2. True

Q.

When it comes to residential wiring, why is a parallel layout used?

Q.

If five resistances, each of value 0.2 ohm are connected in series, what will be the resultant resistance?

Q.

An electric heater which is connected to a 220 V supply line has two resistance coils A and B of $24\Omega$ resistance each. These coils can be used separately (one at a time), in series or in parallel. Calculate the current drawn when :
(a) only one coil A is used.
(b) coils A and B are used in series.
(c) coils A and B are used in parallel.

Q.

Four resistances 2.0 Ω of each are joined end to end to form a square ABCD. The equivalent resistance of the combination between two adjacent corners is:

1. 8 Ω

2. 1 Ω

3. 2 Ω

4. 1.5 Ω

Q.

Why does the potential difference vary across resistors in series connection?

Q.

The resistors $R_1,R_2,R_{3}and{R}_4$ in the figure given below are all equal in value.
What would you expect the voltmeters A, B and C to read assuming that the connecting wires in the circuit have negligible resistance?

Q. Calculate the equivalent resistance of two resistors having resistances $3\Omega$ and $6\Omega$ connected in parallel.

1. $2\Omega$
2. $4\Omega$
3. $6\Omega$
4. $8\Omega$

Q.

In parallel combinationof resistances:
(a) p.d. is same across each resistance
(b) total resistance is increased
(c) current is same in each resistance
(d) all above are true.

Q.

Six equal resistances of $1\Omega$ each are connected to form the sides of a hexagon ABCDEF. Calculate the resistance offered by the combination if the current enters at A and leaves at D.

1. $1\Omega$

2. $1.5\Omega$

3. $2\Omega$

4. $2.5\Omega$

Q.

In the figure, calculate:

(a) the total resistance of the circuit,

(b) the value of R, and

(c) the current flowing in R.

Q.

(a) Draw a circuit diagram showing two lamps, one cell and a switch connected in series.
(b) How can you change the brightness of the lamps?

Q. How to make a series circuit with a switch?