A constant voltage is applied between the two | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) The heat developed in a wire is given by the formula $H = \frac{V^2}{R} t$,where $V$ is the constant voltage,$R$ is the resistance,and $t$ is the

Vedclass · Accepted Answer

both the length and the radius of the wire are doubled.

Vedclass · Answer

(B) The heat developed in a wire is given by the formula $H = \frac{V^2}{R} t$,where $V$ is the constant voltage,$R$ is the resistance,and $t$ is the time.For the heat $H$ to be doubled,the resistance $R$ must be halved.The resistance of a wire is given by $R = \rho \frac{l}{A} = \rho \frac{l}{\pi r^2}$,where $l$ is the length and $r$ is the radius.If both the length $l$ and the radius $r$ are doubled ($l' = 2l$ and $r' = 2r$),the new resistance $R'$ becomes:$R' = \rho \frac{2l}{\pi (2r)^2} = \rho \frac{2l}{4\pi r^2} = \frac{1}{2} \left( \rho \frac{l}{\pi r^2} \right) = \frac{R}{2}$.Since the resistance $R$ is halved,the heat developed $H$ will be doubled.

$A$ constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed is doubled if

Similar Questions

If the heat produced in the $5 \, \Omega$ resistor is $10 \, \text{cal/sec}$, then how much heat in $\text{cal/sec}$ is produced in the $4 \, \Omega$ resistor?

The resistance of a hot tungsten filament is about $10$ times its cold resistance. What will be the resistance of a $100\, W$ and $200\, V$ lamp when not in use? (in $\Omega$)

Two wires of resistances $R_1$ and $R_2$ have temperature coefficients of resistance $\alpha_1$ and $\alpha_2$ respectively. If these are joined in series,the effective temperature coefficient of resistance is:

The ratio of powers dissipated respectively in $R$ and $3R$,as shown in the figure,is:

What is the total current $I$ (in $A$) drawn from the battery in the given circuit?

Vedclass Test Series

Exam Paper Generator

Online Exam Module