Question

Moderators / Stars Challenges

⚠️NO SPAM ⚠️

An electric lamp, whose resistance is 20 ohm, and a conductor of 4 ohm resistance are connected to a 6 volt battery.

Calculate ---›
__________
the total resistance of the circuit.

the current through the circuit and potential difference across the electric lamp and conductor. .

(EXPLAINATION WITH DAIGRAM)


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Answer 1

★ QUESTION :

An electric lamp, whose resistance is 20 Ω, and conductor of 4 Ω resistance are connected to a

6 V battery. Calculate :---

▪️The total resistance of the circuit.

▪️The current through the circuit

▪️The potential difference across the electric lamp and conductor.

________________________________

SOLUTION :

➠ The resistance of the electric lamp, R1 = 20Ω

➠ The resistance of the conductor connected in series, R2 = 4Ω

➠ Then the total resistance in the circuit

→ R = R1 + R2

→ Rs = 20Ω + 4Ω = 24Ω

The total potential difference across the two terminals of the battery V = 6V

Now by Ohm's law, the current passing through the circuit is given by –

➠ I = V/Rs

➠ 6V / 24Ω

➠ 0.25 A.

Applying Ohm's law to the electric lamp and conductor separately.

We get potential difference across the electric lamp,

➠ V1 = 20Ω × 0.25A

➠ 5V ;

and,

that across the conductor, V2 = 4Ω × 0.25A

= 1 V.

Suppose that we like to replace the series combination of electric lamp and conductor by a single equivalent resistance. Its resistance must be such that a potential difference of 6 V across the battery terminals will cause a current of 0.25 A in the circuit. The resistance R of this equivalent register would be –

➠ R = V / 1

= 6 V / 0.25 A

= 24Ω

This is the total resistance of the series circuit ; it is equal to the sum of two resistances.

Answer 2

Explanation:

ANSWER:-

Given:-

• Lamp Resistance AS 20 ohm.
• Conductor of 4 ohm resistance
• Voltage = 6 volt of Battery.

Total Resistance will be

Resistance ( Lamp+Conductor)

= 20 + 4 ohms

= 24 ohm.

We know that:-

$current \times resistance = voltage$

$current = \frac{voltage}{resistance}$

$current = \frac{6}{24}$

current = 0.25 Amperes.

Now , Voltage for Lamp.

Using the same formula:-

Voltage = Current × Resistance

Voltage = 20 × 0.25

Voltage of Lamp is 5 ohm.

Now voltage of Conductor:-

Using the same formula :-

V = IR

Voltage = 0.25 × 4

Voltage = 1 ohm for conductor.

For Diagram:-

• Total Resistance is 24 ohm
• Voltage is 6 volts
• Current is 0.25 ohm.

Refer the Attachment.

Note:-

• Amperes is the SI unit of Current
• Volts is the SI Unit of Voltage
• Ohm is the SI Unit of Resistance