Calculate the equivalent resistance of the following network:

Let R p be the equivalent resistance of resistors connected in parallel. Then, 1 R p = 1 20 + 1 20 ⇒ 1 R p = 1 + 1 20 = 2 20 = 1 10 R p = 10 Ω The equivalent circuit becomes Here, the two, 10 Ω resistors are connected in series. ∴ The equivalent resistance of the circuit, R = 10 Ω + 10 Ω = 20 Ω Hence, the equivalent resistance of the given circuit is 20 Ω .

Three resistors R 1 , R 2 and R 3 are connected in parallel and the combination is connected to a battery, ammeter, voltmeter and key. Draw suitable circuit diagram and obtain an expression for the equivalent resistance of the combination of the resistors.

Let R 1 , R 2 & R 3 be the three resistances connected in parallel to one another and let R be the equivalent resistance of the circuit. A battery of V volts has been applied across the ends of this resistance combination. When the switch of the key is closed, a current I flows in the circuit. According to Ohm's law, I = V R I 1 = V R 1 I 2 = V R 2 I 3 = V R 3 I = I 1 + I 2 + I 3 - - - - ( i ) Substituting the values of I 1 , I 2 & I 3 in the equation ( i ) , we get V R = V R 1 + V R 2 + V R 3 V ( 1 R ) = V ( 1 R 1 + 1 R 2 + 1 R 3 ) 1 R = 1 R 1 + 1 R 2 + 1 R 3

E M B I B E

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2018>Q 3

EASY

10th CBSE

IMPORTANT

Earn 100

Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason.

Important Questions on Electricity

EASY

10th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2018>Q 4

Why are alloys commonly used in electrical heating devices? Give reason.

HARD

10th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2018>Q 5

Show how would you join three resistors, each of resistance

9 Ω

, so that the equivalent resistance of the combination is

13.5 Ω

.

HARD

10th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2018>Q 6

Show how would you join three resistors, each of resistance

9 Ω

, so that the equivalent resistance of the combination is

6 Ω

.

EASY

10th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2018>Q 7

Write Joule's law of heating.

EASY

10th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2018>Q 8

Two lamps, one rated

100 W; 220 V

, and the other

60 W; 220 V

, are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is

220 V

.

EASY

10th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2019>Q 9

Why are the heating elements of electric toasters and electric irons made of an alloy rather than a pure metal?

MEDIUM

10th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2019>Q 10

How will you infer with the help of an experiment that the same current flows through every part of a circuit containing three resistors in series connected to a battery?

MEDIUM

10th CBSE

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR SCIENCE>Chapter 12 - Electricity>CBSE-2019>Q 11

Consider the given circuit and find the current flowing in the circuit and potential difference across the $15 Ω$ resistor when the circuit is closed.

Question Image

Learn and Prepare for any exam you want !

|

|

|

|

|

|

|

|