$(a)$ State $Ohm's$ law. Express it mathematically.
$(b)$ Write symbols used in electric circuits to represent:
$(i)$ Variable resistance.
$(ii)$ Voltmeter.
$(c)$ An electric bulb is rated $220 \, V$ and $100 \, W$. When it is operated on $110 \, V$,what will be the power consumed?
$(b)$ Write symbols used in electric circuits to represent:
$(i)$ Variable resistance.
$(ii)$ Voltmeter.
$(c)$ An electric bulb is rated $220 \, V$ and $100 \, W$. When it is operated on $110 \, V$,what will be the power consumed?
(N/A) $Ohm's$ law states that the current flowing through a conductor is directly proportional to the potential difference across its ends,provided the temperature and other physical conditions remain constant.
Mathematically: $V = IR$,where $V$ is potential difference,$I$ is current,and $R$ is resistance.
$(b)$ $(i)$ Variable resistance: Represented by a resistor symbol with an arrow or a sliding contact.
$(ii)$ Voltmeter: Represented by a circle with a '$V$' inside,having positive and negative terminals.
$(c)$ Given: Rated power $P = 100 \, W$,Rated voltage $V = 220 \, V$.
First,calculate the resistance of the bulb:
$R = \frac{V^2}{P} = \frac{(220)^2}{100} = \frac{48400}{100} = 484 \, \Omega$.
Now,calculate the power consumed at $V_1 = 110 \, V$:
$P_{new} = \frac{V_1^2}{R} = \frac{(110)^2}{484} = \frac{12100}{484} = 25 \, W$.
The power consumed will be $25 \, W$.
Mathematically: $V = IR$,where $V$ is potential difference,$I$ is current,and $R$ is resistance.
$(b)$ $(i)$ Variable resistance: Represented by a resistor symbol with an arrow or a sliding contact.
$(ii)$ Voltmeter: Represented by a circle with a '$V$' inside,having positive and negative terminals.
$(c)$ Given: Rated power $P = 100 \, W$,Rated voltage $V = 220 \, V$.
First,calculate the resistance of the bulb:
$R = \frac{V^2}{P} = \frac{(220)^2}{100} = \frac{48400}{100} = 484 \, \Omega$.
Now,calculate the power consumed at $V_1 = 110 \, V$:
$P_{new} = \frac{V_1^2}{R} = \frac{(110)^2}{484} = \frac{12100}{484} = 25 \, W$.
The power consumed will be $25 \, W$.
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Similar Questions
Draw a circuit diagram for a circuit consisting of a battery of five cells of $2 \text{ V}$ each, a $5 \, \Omega$ resistor, a $10 \, \Omega$ resistor, and a $15 \, \Omega$ resistor, an ammeter, and a plug key; all connected in series. Also, connect a voltmeter to record the potential difference across the $15 \, \Omega$ resistor and calculate:
$(i)$ the electric current passing through the above circuit and
$(ii)$ the potential difference across the $5 \, \Omega$ resistor when the key is closed.
$(i)$ the electric current passing through the above circuit and
$(ii)$ the potential difference across the $5 \, \Omega$ resistor when the key is closed.
Medium
View SolutionDraw a schematic diagram of an electric circuit (in the "on" position) consisting of a battery of five cells of $2\, V$ each, a $5\, \Omega$ resistor, a $8\, \Omega$ resistor, a $12\, \Omega$ resistor and a plug key, all connected in series. An ammeter is put in the circuit to measure the electric current through the resistors and a voltmeter is connected so as to measure the potential difference across the $12\, \Omega$ resistor.
Calculate the reading shown by the
$(a)$ ammeter
$(b)$ voltmeter in the given electric circuit.
Calculate the reading shown by the
$(a)$ ammeter
$(b)$ voltmeter in the given electric circuit.
Difficult
View Solution$(a)$ What do the following symbols represent in a circuit? Write the name and one function of each.
$(b)$ Draw a schematic diagram of a circuit consisting of a battery of $12 \, V$,three resistors of $5 \, \Omega$,$10 \, \Omega$,and $20 \, \Omega$ connected in parallel,an ammeter to measure the total current through the circuit,and a voltmeter to measure the potential difference across the combination of resistors.
$(c)$ State any one advantage of connecting electrical devices in parallel with the mains instead of connecting them in series in a household circuit.
$(b)$ Draw a schematic diagram of a circuit consisting of a battery of $12 \, V$,three resistors of $5 \, \Omega$,$10 \, \Omega$,and $20 \, \Omega$ connected in parallel,an ammeter to measure the total current through the circuit,and a voltmeter to measure the potential difference across the combination of resistors.
$(c)$ State any one advantage of connecting electrical devices in parallel with the mains instead of connecting them in series in a household circuit.
Medium
View SolutionRead the following statements carefully and state whether each statement is true or false:
$(i)$ The quantity of charge flowing past a point multiplied by time is current.
$(ii)$ The flow of charge through a conducting wire connected to a cell is the result of a chemical reaction inside the cell.
$(iii)$ The resistivity of all pure metals increases with an increase in temperature.
$(iv)$ Ohm's law is a relation between the power used in a circuit to the current and the potential difference.
$(v)$ $A$ series circuit has only one conducting path for the electrons that move through it; a parallel circuit has multiple conducting paths.
$(vi)$ $A$ conducting wire offers resistance to the flow of electrons because electrons repel each other in the wire.
$(i)$ The quantity of charge flowing past a point multiplied by time is current.
$(ii)$ The flow of charge through a conducting wire connected to a cell is the result of a chemical reaction inside the cell.
$(iii)$ The resistivity of all pure metals increases with an increase in temperature.
$(iv)$ Ohm's law is a relation between the power used in a circuit to the current and the potential difference.
$(v)$ $A$ series circuit has only one conducting path for the electrons that move through it; a parallel circuit has multiple conducting paths.
$(vi)$ $A$ conducting wire offers resistance to the flow of electrons because electrons repel each other in the wire.
Medium
View Solution$(a)$ Three resistors $R_{1}, R_{2}$ and $R_{3}$ are connected in parallel and the combination is connected to a battery,ammeter,voltmeter,and key. Draw a suitable circuit diagram. Obtain an expression for the effective resistance of the combination of resistors in parallel.
$(b)$ Why are electric bulbs filled with chemically inactive nitrogen or argon?
$(c)$ What is meant by the statement that the rating of a fuse in a circuit is $5 \ A$?
$(b)$ Why are electric bulbs filled with chemically inactive nitrogen or argon?
$(c)$ What is meant by the statement that the rating of a fuse in a circuit is $5 \ A$?
Medium
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