English

When a switch is in OFF position, circuit starting from the positive terminal of the cell stops at the switch. circuit is open. no current flows through it. current flows after some time.

Advertisements
Advertisements

Question

When a switch is in OFF position,

  1. circuit starting from the positive terminal of the cell stops at the switch.
  2. circuit is open.
  3. no current flows through it.
  4. current flows after some time. 

Choose the combination of correct answer from the following.

Options

  • all are correct

  • (ii) and (iii) are correct

  • only (iv) is correct

  • only (i) and (ii) are correct

MCQ
Advertisements

Solution

(ii) and (iii) are correct

Explanation:

  • When a switch is in the OFF position:

    • The circuit is open (meaning there is a break in the circuit).

    • No current flows through it because an open circuit prevents the flow of electricity.

The other options are not correct because:

  • Option (i) (“circuit starting from the positive terminal of the cell stops at the switch”) is not a complete statement. It doesn’t fully explain the condition of the circuit when the switch is OFF.

  • Option (iv) (“current flows after some time”) is incorrect because no current flows when the switch is OFF.

So, the correct combination is (ii) and (iii).

shaalaa.com
  Is there an error in this question or solution?
Chapter 14: Electric Current and Its Effects - MULTIPLE CHOICE QUESTIONS [Page 76]

APPEARS IN

NCERT Exemplar Science [English] Class 7
Chapter 14 Electric Current and Its Effects
MULTIPLE CHOICE QUESTIONS | Q 4. | Page 76

RELATED QUESTIONS

Why does the connecting cord of an electric heater not glow hot while the heating element does?


Write down the formula for the heat produced when a current I is passed through a resistor R for time t.


Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.


A resistance of 25 Ω is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.


The elements of electrical heating devices are usually made of:

(a) tungsten
(b) bronze
(c) nichrome
(d) argon


Statement 1 : Electric current ( flow of electrons ) creates heat in the resistor.
Statement 2 : Heat in the resistor is created according to the rule of energy conservation.
Explain Statement 1 with the help of Statement 2.


B1, B2 and B3 are three identical bulbs connected as shown in Figure. When all the three bulbs glow, a current of 3A is recorded by the ammeter A.

  1.  What happens to the glow of the other two bulbs when the bulb B1 gets fused?
  2. What happens to the reading of A1, A2, A3 and A when the bulb B2 gets fused?
  3. How much power is dissipated in the circuit when all the three bulbs glow together?

 


It would cost a man Rs. 3.50 to buy 1.0 kW h of electrical energy from the Main Electricity Board. His generator has a maximum power of 2.0 kW. The generator produces energy at this maximum power for 3 hours. Calculate how much it would cost to buy the same amount of energy from the Main Electricity Board.


The electric fuse works on the Joule heating principle.


Write an expression for the amount of heat produced in a resistor when an electric current is passed through it stating the meanings of the symbols used.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×