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Why Should the Resistance Of: an ammeter be very small?

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प्रश्न

Why should the resistance of: 

 an ammeter be very small?

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उत्तर

 An ammeter should have a very low resistance so that it will not change the value of the current flowing in the circuit.

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अध्याय 4: Electricity - Exercise 2

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लखमीर सिंग Physics [English] Class 10
अध्याय 4 Electricity
Exercise 2 | Q 20.1

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संबंधित प्रश्न

Fill in the blank:

To increase the effective resistance in a circuit the resistors are connected in _____________.


Draw the electrical symbols of the following components and state its use

Wire crossing


By what name is the physical quantity coulomb/second called?


An electric circuit consisting of a 0.5 m long nichrome wire XY, an ammeter, a voltmeter, four cells of 1.5 V each and a plug key was set up.

(i) Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points 'X' and 'Y' and the electric current flowing through XY.


A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 Ω, 0.4 Ω, 0.5 Ω and 0.12 Ω. How much current would flow through the 12 Ω resistor?


The figure given below shows an electric circuit in which current flows from a 6 V battery through two resistors. 

 

  1. Are the resistors connected in series with each other or in parallel?
  2. For each resistors, state the p.d. across it.
  3. The current flowing from the battery is shared between the two resistors. Which resistor will have bigger share of the current?
  4. Calculate the effective resistance of the two resistors.
  5. Calculate the current that flows from the battery.

The lamps in a house hold circuit are connected in parallel because:

(a) this way they required less current
(b) if one lamp fails the others remain lit
(c) this way they require less power
(d) if one lamp fails the other also fail


Two resistors of 2.0 Ω and 3.0 Ω are connected (a) in series (b) in parallel, with a battery of 6.0 V and negligible internal resistance. For each case draw a circuit diagram and calculate the current through the battery. 


Give two uses of conductors.

A battery of e.m.f. 15 V and internal resistance 3 ohm is connected to two resistors of resistance 3 ohm and 6 ohm in series. Find:
(i) The current through the battery,
(ii) The p.d. between the terminals of the battery.


A bulb marked 12 V, 24 W operates on a 12 volt car battery for 20 minutes. Calculate:
(i) The current flowing through it, and
(ii) The energy liberated.


The circuit diagram (Fig.) shows a battery of e.m.f. 6 volts and internal
resistance of 0.8 Ω oonnected in series. Find the
(a) Current reoorded by the ammeter,
(b) P.d. across the terminals of the resistor B,
( c) Current passing through each of the resistors B, C and D, and
( d) P.d. across the terminals of the battery.


Explain with the help of a diagram how does 'short circuiting' occur in an electric kettle.


Electrical power P is given by the expression P = (Q × V) ÷ time

(a) What do the symbols Q and V represent?

(b) Express the power P in terms of current and resistance explaining the meanings of symbols used there in.


What is meant by internal resistance of a cell?


Small amounts of electrical current are measured in milliampere (mA). How many milliampere are there in 0.25 A ?


State whether true or false. If false, correct the statement.

Current can produce magnetic field.


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

Name any two devices, which are working on the heating effect of the electric current.


Find the odd one out.

Loudspeaker, Bar magnet/magnet, Electric motor, Microphone.


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