The table given below gives the resistivity of three samples in ohm metre
Samples
$A$
$B$
$C$
Resistivity
$1.6 \times 10^{-8}$
$7.5 \times 10^{17}$
$44 \times 10^{-6}$
$(a)$ Which of them is a good conductor ? Which is an insulator ? Why?
$(b)$ $A$ wire of resistance $4$ ohm is doubled on it. Calculate the new resistane of the wire.
The table given below gives the resistivity of three samples in ohm metre
| Samples | $A$ | $B$ | $C$ |
| Resistivity | $1.6 \times 10^{-8}$ | $7.5 \times 10^{17}$ | $44 \times 10^{-6}$ |
$(a)$ Which of them is a good conductor ? Which is an insulator ? Why?
$(b)$ $A$ wire of resistance $4$ ohm is doubled on it. Calculate the new resistane of the wire.
$(a)$ $A$ is a conductor and $B$ is an insulator. Since the metals and alloys have very good resistivity in the range of $10^{-8}$ to $10^{-6} \Omega m$ they are very good conductors of electricity while insulators have resistivity of the order of $10^{12}$ to $10^{17} \Omega m$ are insulator.
$(b)$ If the wire of resistance $4 \Omega$ doubled on it, then the new resistance will become four times and $R _{n}=n^{2} R ,$ where $n$ is the times the wire is elongated.
Similar Questions
When do we say that the resistors are connected in parallel ?
When do we say that the resistors are connected in parallel ?
What is the resistance of an electric arc lamp, if the lamp uses $20\, A$ when connected to $220$ volt line ?
What is the resistance of an electric arc lamp, if the lamp uses $20\, A$ when connected to $220$ volt line ?
Three $V -I$ graphs are drawn individually for two resistors and their series combination. Out of $A, B,C$ which one represents the graph for series combination of the other two. Give reason for your answer.
Three $V -I$ graphs are drawn individually for two resistors and their series combination. Out of $A, B,C$ which one represents the graph for series combination of the other two. Give reason for your answer.
Two lamps, one is rated $100\, W$ at $220\, V$, and the other $60 \,W$ at $220\, V ,$ are connected in parallel to a $220\, V$ supply. Find the current drawn from the supply line.
Two lamps, one is rated $100\, W$ at $220\, V$, and the other $60 \,W$ at $220\, V ,$ are connected in parallel to a $220\, V$ supply. Find the current drawn from the supply line.
$(i)$ Draw a circuit diagram to show how two resistors are connected in series.
$(ii)$ In a circuit, if the two resistors of $5$ ohm and $10$ ohm are connected in series, how does the current passing through the two resistors compare ?
$(i)$ Draw a circuit diagram to show how two resistors are connected in series.
$(ii)$ In a circuit, if the two resistors of $5$ ohm and $10$ ohm are connected in series, how does the current passing through the two resistors compare ?