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Thursday 25 February 2021

CBSE Class 7 Science - MCQ and Online Tests - Unit 14 - Electric Current and Its Effects

CBSE Class 7 Science – MCQ and Online Tests – Unit 14 – Electric Current and Its Effects

Every year CBSE students attend Annual Assessment exams for 6,7,8,9,11th standards. These exams are very competitive to all the students. So our website provides online tests for all the 6,7,8,9,11th standards’ subjects. These tests are also very effective and useful for those who preparing for any competitive exams like Olympiad etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE syllabus. While attempting these, our students can identify their weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly

CBSE Class 7 Science – MCQ and Online Tests – Unit 14 – Electric Current and Its Effects

Question 1.
The amount of heat produced in a wire depends on
(a) material
(b) length
(c) thickness
(d) all of these

Question 2.
When a switch is in OFF position.
(i) circuit starting from the positive terminal of the cell stops at the switch.
(ii) circuit is open.
(iii) no current flows through it.
(iv) current flows after some time.
Choose the combination of correct answer from the following:
(a) all are correct
(b) (ii) and (iii) are correct
(c) only (iv) is correct
(d) only (i) and (ii) are correct

Answer: (b) (ii) and (iii) are correct

Question 3.
Where can the key or switch be placed in the circuit?
(a) Left side of the battery
(b) Right side of the battery
(c) Can be placed anywhere in the circuit
(d) Near the positive terminal of the bulb

Answer: (c) Can be placed anywhere in the circuit

Question 4.
Which mark is necessary on electric appliances?
(a) AGMARK
(b) ISI
(c) FICCI
(d) KSK

Question 5.
Which one of the following is based on the heating effect of current?
(a) Geyser
(b) Hair dryer
(c) Immersion rod
(d) All of these

Question 6.
The coil of wire contained in an electric heater is known as
(a) component
(b) element
(c) circuit
(d) spring

Question 7.
In making a battery
(a) positive terminal of one cell is connected to the negative terminal of the next cell
(b) positive terminal of one cell is connected to the positive terminal of the next cell
(c) negative terminal of one cell is connected to the negative terminal of the next cell
(d) none of the above

Answer: (a) positive terminal of one cell is connected to the negative terminal of the next cell

Question 8.
Which of the following precautions need not be taken while using electric gadgets / appliances/circuit?
(a) We should never touch a lighted electric bulb connected to the mains.
(b) We should never experiment with the electric supply from the mains or a generator or an inverter.
(c) We should never use just any wire or strip of metal in place of a fuse.
(d) We should never turn the switch in ON position.

Answer: (d) We should never turn the switch in ON position.

Question 9.
When an electric current flows through a copper wire AB as shown in Figure, the wire

(a) deflects a magnetic needle placed near it
(b) becomes red hot
(c) gives electric shock
(d) behaves like a fuse

Answer: (a) deflects a magnetic needle placed near it

Question 10.
Choose the statement which is not correct in the case of an electric fuse.
(a) Fuses are inserted in electric circuits of all buildings.
(b) There is a maximum limit on the current which can safely flow through the electric circuits.
(c) There is a minimum limit on the current which can safely flow in the electric circuits.
(d) If a proper fuse is inserted in a circuit it will blow off if current exceeds the safe limit.