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प्रश्न
Fill in the folloing blank with suitable words:
A current is a flow of ............... .For this to happen there must be a ............... circuit.
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उत्तर
A current is a flow of electrons. For this to happen, there must be a closed circuit.
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संबंधित प्रश्न
Compare how an ammeter and a voltmeter are connected in a circuit.
Fill in the folloing blank with suitable words:
Current is measured in ............... using an ............... placed in ............... in a circuit.
What is an Ammeter? How is It Connected in a Circuit? Draw a Diagram to Illustrate Your Answer.
A p.d. of 6 V is applied to two resistors of 3 Ω and 6 Ω connected in parallel. Calculate:
(a) the combined resistance
(b) the current flowing in the main circuit
(c) the current flowing in the 3 Ω resistor.
Christmas tree lamps are usually wired in series. What happens if one lamps breaks?
Consider the circuit given below when A, B and C are three identical light bulbs of constant resistance. 
(a) List the bulbs in order of increasing brightness.
(b) If C burns out, what will be the brightness of A now compared with before?
(c) If B burns out instead, what will be the brightness of A and C compared with before?
Match the pairs.
| ‘A’ Group | ‘B’ Group |
| 1. Free electrons | a. V/R |
| 2. Current | b. Increases the resistance in the circuit |
| 3. Resistivity | c. Weakly attached |
| 4. Resistances in series | d. VA/LI |
If the potential differences between two parts of a thundercloud is 10s V,
what is the amount of energy given up during the passage of 20 coulombs?
(a)2x10-7J
(b)200J
(c)Sx106 j
(d)2x 109J
(e)2x 1010 J
A wire is passed through a piece of cardboard as shown in fig .. An electric current flows vertically down the wire and then flows back up. The two sections of the write are observed to repel each other.
(a) Wi th the aid of a diagram, describe how you would plot the magnetic field lines on the card .
(b) Sketch the magnetic field patterns around both the sections of the wire. Use your sketch to explain why the two sections repel each other.
(c) The repulsive force between the two sections is small. What changes could be made to increase it?
Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply. The resistance of each heater
Two electric bulbs rated 100 W; 220 V and 60 W; 220 V are connected in parallel to electric mains of 220 V. Find the current drawn by the bulbs from the mains.
True or False – If False give the correct answer
The representation of the electric current is A
A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be roughly
Problems for practice:
If 3A current flows through a circuit, then convert the current in terms of a milliampere.
