A heating coil is labelled 100, W,220, V. The | vedclass

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

Question

(B) The power $P$ of a heating coil is given by $P = V^2 / R$,where $V$ is the voltage and $R$ is the resistance.Initially,$P_1 = 100\, W$ and $V = 22

Vedclass · Accepted Answer

$400$

Vedclass · Answer

(B) The power $P$ of a heating coil is given by $P = V^2 / R$,where $V$ is the voltage and $R$ is the resistance.Initially,$P_1 = 100\, W$ and $V = 220\, V$. Thus,$R = V^2 / P_1$.When the coil is cut into two equal halves,the resistance of each piece becomes $R' = R / 2$.When these two pieces are connected in parallel,the equivalent resistance $R_{eq}$ is given by $1 / R_{eq} = 1 / R' + 1 / R' = 2 / R' = 2 / (R / 2) = 4 / R$.Therefore,$R_{eq} = R / 4$.The new power consumed is $P_2 = V^2 / R_{eq} = V^2 / (R / 4) = 4 	imes (V^2 / R) = 4 	imes P_1$.Substituting the value,$P_2 = 4 	imes 100\, W = 400\, W$.Since $1\, W = 1\, J/s$,the energy liberated per second is $400\, J/s$.

$A$ heating coil is labelled $100\, W$,$220\, V$. The coil is cut in half and the two pieces are joined in parallel to the same source. The energy now liberated per second is .............. $J/s$.

Similar Questions

When a resistance of $2\,\Omega$ is connected across the terminals of a cell,the current is $0.5\,A$. When the resistance is increased to $5\,\Omega$,the current is $0.25\,A$. The $e.m.f.$ of the cell is ................. $V$.

An external resistance $R$ is connected to a battery of $e.m.f.$ $V$ and internal resistance $r$. The joule heat produced in resistor $R$ is maximum when $R$ is equal to

In the circuit shown in the figure,the currents in different branches and the value of one resistor are given. Then,the potential at point $B$ with respect to point $A$ is $.......V$.

All wires have the same resistance $r$. The equivalent resistance between $A$ and $B$ is $R$. Now,if the keys $K_1$ and $K_2$ are closed,what will be the new equivalent resistance?

In the given circuit,$E_1 = E_2 = E_3 = 2 \, V$ and $R_1 = R_2 = 4 \, \Omega$. What is the current flowing between points $A$ and $B$ (in $, A$)?

Vedclass Test Series

Exam Paper Generator

Online Exam Module