AP Board 7th Class Science Solutions Chapter 7 Electricity – Current and Its Effect

AP State Syllabus AP Board 7th Class Science Solutions Chapter 7 Electricity – Current and Its Effect Textbook Questions and Answers.

AP State Syllabus 7th Class Science Solutions 7th Lesson Electricity – Current and Its Effect

7th Class Science 7th Lesson Electricity – Current and Its Effect Textbook Questions and Answers

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Question 1.
Draw the symbols of the following electric components.
a) Cell
b) Battery
c) Switch
d) Electric bulb
Answer:
a) Symbol for cell: The longer line denotes the positive terminal, and the thicker, small line denotes the negative terminal.

b) Symbol for battery: Two or more cells joined together form a battery.

c) Symbol for switch: Switch is also called key. Switch is open.

d) Symbol for electric bulb: Electric bulb in on position.

Question 2.
Draw an electric circuit diagram consisting of a cell, a bulb and an electric switch.
Answer:
Electric Circuit diagram:

Question 3.
In a series connection of bulbs, if one bulb fails, why do all other bulbs go OFF?
Answer:

1. In a series electric circuit, electricity has only one path to flow through.
2. In series connection of bulbs, if one bulb fails, the circuit breaks and current do not flow in the circuit.
3. So other bulbs in the series connection of bulbs do not glow’and they go OFF.

Question 4.
Write the difference between series connection and parallel connection.
Answer:

Series Connection	Parallel Connection
Electricity has only one path to flow.	Electricity has more than one path to flow.
All the electrical components are connected in this path.	Each bulb in the circuit is connected in separate path through which electricity can flow.

Question 5.
What is the advantage of Miniature Circuit Breaker?
Answer:

1. The advantage miniature circuit breakers have over fuses is that they can reset (manually or automatically) to restore normal operation.
2. Fuses need to be replaced after every single operation.

Question 6.
Fill in the blanks.
a) Longer line in the symbol for a cell represents its ………… terminal.
b) Smaller line in the symbol for a cell represents its ………… terminal.
c) The combination of two or more cells is called a ………… .
d) Safety device used in electric circuit is ………… .
e) The device used to close or open an electric circuit is ………… .
Answer:
a) positive
b) negative
c) battery
d) fuse
e) switch

Question 7.
Mark T’ if the statement is true and F’ if it is false. Give reasons for choice of answer.
a) In series circuit the electricity has only one path. (T/F)
b) In parallel circuit the electricity has more than one path. (T/F)
c) To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell. (T/F)
d) When the electric current through the fuse exceeds a certain limit the fuse wire
melts and breaks. (T/F)
e) The switch is used to close or open an electric circuit. (T/F)
Answer:
a) T
b) T
c) F
d) T
e) T

Question 8.
Choose the correct answer.

i) Arun buys four bulbs of 15 W, 40 W, 60 W and 100 W respectively. Which one should be use in his room as a night bulb?
A) 15 W
B) 40 W
C) 60 W
D) 100 W
Answer:
A) 15 W

ii) Device used to close or open an electric circuit is ( C )
A) Electric bulb
B) Battery
C) Switch
D) Fuse
Answer:
C) Switch

iii) Which one of the following is used for light source? ( D )
A) Cassette player
B) Electric mixer
C) Rice Cooker
D) Table lamp
Answer:
D) Table lamp

iv) Safety device used in electric circuit is ( D )
A) Electric bulb
B) Battery
C) Switch
D) Fuse
Answer:
D) Fuse

Question 9.
Visit your classmates houses. Find out the meter readings of three months. Record your observations. Ask your parents about how electricity bill is paid?
Answer:

Question 10.
Draw the symbols of the following electric components.
Answer:

Question 11.
Draw the circuit diagram for the following series connection.

Answer:

Question 12.
Match the following.

Answer: