A wire of resistance of $10\, ohm$ is bent in the form of a closed circle. What is the effective resistance between the two points at the ends of any diameter of this circle ?
A wire of resistance of $10\, ohm$ is bent in the form of a closed circle. What is the effective resistance between the two points at the ends of any diameter of this circle ?
Each of the two semicircles between the two ends of a diameter has a resistance of $10 / 2$ $=5$ ohm. These two resistors are in parallel between the two ends of the diameter. Thus, the
effective resistance $R =\frac{ R _{1} R _{2}}{ R _{1}+ R _{2}}=\frac{5 \times 5}{5+5}=2.5 ohm$
Similar Questions
Define resistivity of a material.
Define resistivity of a material.
Out of the two wires $X$ and $Y$ shown below which one has greater resistance. Justify your answer.
Out of the two wires $X$ and $Y$ shown below which one has greater resistance. Justify your answer.
An electric bulb rated $220 \,V , 60\, W$ is working at full efficiency.
$(i)$ State the resistance of the coil of the bulb. Another identical bulb is connected in series with the first one and the system is connected across the mains as shown below. $(ii)$ State the rate of conversion of energy in each bulb. $(iii)$ Calculate the total power. $(iv)$ What will be the total power if the bulbs are connected in parallel ?
An electric bulb rated $220 \,V , 60\, W$ is working at full efficiency.
$(i)$ State the resistance of the coil of the bulb. Another identical bulb is connected in series with the first one and the system is connected across the mains as shown below. $(ii)$ State the rate of conversion of energy in each bulb. $(iii)$ Calculate the total power. $(iv)$ What will be the total power if the bulbs are connected in parallel ?
The following table gives the resistivity of three samples
Sample
$A$
$B$
$C$
Resistivity
$1.6 \times 10^{-8} \Omega m$
$5.2 \times 10^{-8} \Omega m$
$100 \times 10^{-6} \Omega m$
Which of them is suitable for heating elements of electrical appliances and why ?
The following table gives the resistivity of three samples
| Sample | $A$ | $B$ | $C$ |
| Resistivity | $1.6 \times 10^{-8} \Omega m$ | $5.2 \times 10^{-8} \Omega m$ | $100 \times 10^{-6} \Omega m$ |
Which of them is suitable for heating elements of electrical appliances and why ?
Define electric power. Give its $SI$ units and write its mathematical equation.
Define electric power. Give its $SI$ units and write its mathematical equation.