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Define an electric current. - Science

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प्रश्न

Define an electric current.

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उत्तर १

An electric current is measured by the amount of electric charge moving per unit time at any point in the circuit.

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उत्तर २

The magnitude of an electric current is the number of electric charges flowing through a conductor in one second.

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 2: Electricity - Evaluation [पृष्ठ ३४]

APPEARS IN

सामाचीर कलवी Science - Term 2 [English] Class 7 TN Board
अध्याय 2 Electricity
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सामाचीर कलवी Science [English] Class 9 TN Board
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लखमीर सिंग Physics (Science) [English] Class 10
अध्याय 1 Electricity
Exercise 2 | Q 26.1 i.

वीडियो ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्न

1 A = _________ mA

  1. 102
  2. 103
  3. 10-3
  4. 10-6

Choose the correct alternative and rewrite the following sentence.

When the resistance of a conductor increases, the current will ________ increase.


How many microamperes are there in 1 ampere?


What Makes an Electric Current Flow in a Wire?


<p> Define the unit of electric current (or Define ampere).


What is an Ammeter? How is It Connected in a Circuit? Draw a Diagram to Illustrate Your Answer.


One coulomb of charge flows through any cross-section of a conductor in 1 second. What is the current flowing through the conductor?


Three resistors are connected as shown in the diagram.


Through the resistor 5 ohm, a current of 1 ampere is flowing.

(i) What is the current through the other two resistors?
(ii) What is the p.d. across AB and across AC?
(iii) What is the total resistance


In the circuit diagram  given below, three resistors R1, R2, and R3 of 5 Ω, 10 Ω and 30 Ω, respectively are connected as shown 

  

Calculate:

  1. current through each resistor.
  2. total current in the circuit. 
  3. total resistance in the circuit.

A battery and three lamps are connected as shown: 

 

Which of the following statements about the currents at X, Y and Z is correct?
(a) The current at Z is greater than that at Y.
(b) The current at Y is greater than that at Z.
(c) The current at X equals the current at Y.
(d) The current at X equals the current at Z. 

 


Ten bulbs are connected in a series circuit to a power supply line. Ten identical bulbs are connected in a parallel circuit to an identical power supply line. 

(c) In which circuit, if one bulb blows out, all other will stop glowing?


Two lamps, one rated 40 W at 220 V and the other 60 W at 220 V, are connected in parallel to the electric supply at 220 V.  


(a) Draw a circuit diagram to show the connections.
(b) Calculate the current drawn from the electric supply.
(c) Calculate the total energy consumed by the two lamps together when they operate for one hour.


State three factors on which the heat produced by an electric current depends. How does it depend on these factors? 


A wire of uniform thickness with a resistance of 27Ω is cut into three equal pieces and they are joined in parallel. Find the equivalent resistance of the parallel combination. 


Three resistors of 6.0 𝛀, 2.0𝛀 and 4.0𝛀 are joined to an ammeter A and a cell of e.m.f. 6.0 V as
shown in fig 8.52 Calculate:
(a) the effective resistance of the circuit and
(b) the reading of ammeter. 

 


Distinguish between an open and a closed circuit.


What do you mean by electric current?

Name the physical quantity which equals the product of voltage and current.

What do you mean by watt-hour?

State two important precautions you should observe while using electricity?

Can a copper wire be used as a fuse wire?

What type of electricity is supplied to us at houses?

Find the effective resistance in the following circuit diagrams (Fig.):


A current of 0.3 A is flowing through a branch of 6 Ω resistors in a junction as shown in fig. . Calculate the
(a) P.d. across the junction XY,
(b) Current flowing through 9Ω and 24Ω
( c) P.d. across 24 Ω resistor, and
( d) e.m.f. of the cell.


If a fuse contains a 5 A fuse wire and the voltage is 240 V, what is the maximum power (wattage) which may be taken from the circuit?


Name the principle on which a transformer works.


What is the function of a step-up transformer?


1 kWh = `(1 "volt" xx 1 "ampere" xx "_________")/1000`


Complete the following:

1 kWh = _________ J


A bulb of 40 W is used for 12.5 h each day for 30 days. Calculate the electrical energy consumed.


A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:

The energy dissipated in the bulb in 10 minutes.


An electric kettle is rated 2.5 kW, 250 V. Find the cost of running the kettle for two hours at Rs. 5.40 per unit.


Fill in the blank :

1 mA = ............................. A.


State whether the following statement is True or False:

The SI unit of charge is the coulomb. 


Answer the following question.
What is the function of a galvanometer in a circuit?


Explain, why the potential difference across the terminals of a cell is more when the cell is not in use than it is when the cell is being used.


What is meant by internal resistance of a cell?


Match the items in column-I to the items in column-II:

Column - I Column - II
(i) electric current (a) volt
(ii) potential difference (b) ohm meter
(iii) specific resistance (c) watt
(iv) electrical power (d) joule
(v) electrical energy (e) ampere

Match the following:

1. 1 mA a. series
2. 1 pA b. ohmmeter
3. Ammeter  c. 10-6 ampere
4. Electrical resistivity d. 10-3 ampere

What are the effects of electric current?


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