Equivalent Resistance in Series Circuit

Q.

For the circuit shown in the following diagram what is the value of [3 MARKS]

(i) current through 6 ohm resistor

(ii) potential difference across 12 ohm

Q.

What are three characteristics of a series circuit?

Q.

How do you find the resistance of a wire?

Q.

Resistors $R_1$, $R_2$ and $R_3$ having values 5$\Omega$, 10$\Omega$, and 30$\Omega$ respectively are connected in parallel across a battery of 12V. Calculate [3 MARKS]

(a) the current through each resistor

(b) the total current in the circuit and

(c) the total circuit resistance.

Q.

Two equal resistance when connected in series to a battery, consume electric power of $60W$. If these resistances are now connected in parallel combination to the same battery, the electric power consumed will be:

1. $60W$

2. $240W$

3. $30W$

4. $120W$

Q.

State true or false.
Tungsten is used almost exclusively for filament of incandescent lamps because tungsten has a high melting point (${3380}^{\circ }$C) and becomes incandescent (i.e., emits light at a high temperature) at $2400K$.

1. True
2. False

Q.

Three resistances each of 4 Ohm are connected in the form of an equilateral triangle. The effective resistance between any two corners is:

1. 12 Ohm

2. Ohm

3. 8 Ohm

4. Ohm

Q.

A circuit contains two unequal resistances in parallel.

1. Current is same in both

2. Large current flows in the resistor with high resistance

3. Potential difference across each is same

4. Smaller resistance has smaller conductance.

Q. The effective resistance between the points A and B in the figure is

1. $5\Omega$
2. $2\Omega$
3. $3\Omega$
4. $4\Omega$

Q. In the network shown in figure, the equivalent resistance between points X and Y will be_____.

1. $r$
2. $\frac{r}{2}$
3. $2r$
4. $\frac{r}{3}$

Q.

What is electrical resistivity? In a series electrical circuit comprising a resistor made up of a metallic wire, the ammeter reads 5 A. The reading of the ammeter decreases to half when the length of the wire is doubled. Why?

Q.

How would the strength of magnetic field due to current-carrying loop be affected if the radius of loop is reduced to half of its original value?

Q. Question 17
An electric heater of resistance $8\Omega$ draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.

Q.

In an electrical circuit, two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be

1. 5J

2. 10J

3. 20J

4. 30J

Q. Find the effective resistance in the following circuit.

1. $8\Omega$
2. $5\Omega$
3. $7\Omega$
4. $10\Omega$

Q.

A cylindrical copper rod is reformed to thrice its original length. The resistance between its ends before the change was$R$, now its new resistance becomes

1. $8R$

2. $4R$

3. $9R$

4. $R$

Q. Calculate the electric current flowing through the $20.5\Omega$ resistor in the following circuit.

1. $1.366A$
2. $0.366A$
3. $2.366A$
4. $3.366A$

Q.

The unit of specific resistance is

1. Ohm/cm²

2. Ohm/cm

3. Ohm-cm

4. (Ohm-cm)^–1

Q.

In parallel combination, the equivalent resistance:

1. decreases

2. may increase or decrease according to the situation

3. no particular observation

4. increases

Q. Find the equivalent resistance between points $A$ and $B$.

Q. Question 1 (a)
Judge the equivalent resistance when the following are connected in parallel−(a) $1\Omega$ and ${10}^6\Omega$.

Q.

Simplify the following circuit and find the boolean polynomial

1. $p\vee (q\wedge r)$

2. $p\wedge (q\vee r)$

3. $p\vee (q\vee r)$

4. $p\wedge (q\wedge r)$

Q. Calculate the effective resistance between the points A and Bin the circuit shown in figure

Q. (a) On which factors does the resistance of a conductor depend? Define resistivity and state its SI unit.
(b) Give the value of total resistance and total current flowing in the given circuit.

Q. Obtain an expression for effective resistance when two resistors are connected in
(a) series
(b) parallel

Q.

For a constant resistance, the correct relation between heat produced (H) and electric current (I) flowing is:

1. $\text{H}\propto {\text{I}}^{-1}$
2. $\text{H}\propto \text{I}$
3. $\text{H}\propto {\text{I}}^2$
4. $\text{H}\propto {\text{I}}^{-0.5}$

Q. In the circuit shown in the figure calculate the equivalent resistance between the points a and b.

Q.

How does the strength of the magnetic field at the center of a circular coil of wire depend on

(a). radius of the coil?

(b). number of turns of wire in the coil?

(c). strength of the current flowing in the coil?

Q. The equivalent resistance between the points a and b of the electrical network shown in the figure is

1. $6r$
2. $4r$
3. $2r$
4. $r$

Q. Four resistors $5\Omega ,6\Omega ,4\Omega$ and $8\Omega$ are connected in (a) series and in (b) parallel. Find the equivalent resistance in each case.