Question:

A $40\, \mu F$ capacitor in a defibrillator is charged to $3000 \,V$. The energy stored in the capacitor is sent through the patient during a pulse of duration $2\, ms$. The power delivered to the patient is

Updated On: Jun 23, 2023

45 kW
90 kW
180 kW
360 kW

Hide Solution

Verified By Collegedunia

The Correct Option is B

Solution and Explanation

A capacitor is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. The energy stored in a capacitor $=\frac{1}{2} C V^{2}$ Given, $C=40\, \mu F =40 \times 10^{-6} F , V=3000\, V$ $\therefore E=\frac{1}{2} \times 40 \times 10^{-6} \times(3000)^{2}$ $=180\, J$ Also $1 \,W =1 \,J / s$ $\therefore 2\, ms =2 \times 10^{-3} s$ Hence, power $=\frac{180 J }{2 \times 10^{-3} s }$ $=90 \times 10^{3} W =90\, kW$

Was this answer helpful?

Questions Asked in AIIMS exam

View More Questions

Concepts Used:

Electrostatic Potential and Capacitance

Electrostatic Potential

The potential of a point is defined as the work done per unit charge that results in bringing a charge from infinity to a certain point.

Some major things that we should know about electric potential:

They are denoted by V and are a scalar quantity.
It is measured in volts.

Capacitance

The ability of a capacitor of holding the energy in form of an electric charge is defined as capacitance. Similarly, we can also say that capacitance is the storing ability of capacitors, and the unit in which they are measured is “farads”.

The capacitor is in Series and in Parallel as defined below;

In Series

Both the Capacitors C₁ and C₂ can easily get connected in series. When the capacitors are connected in series then the total capacitance that is C_totalis less than any one of the capacitor’s capacitance.

In Parallel

Both Capacitor C₁ and C₂ are connected in parallel. When the capacitors are connected parallelly then the total capacitance that is C_total is any one of the capacitor’s capacitance.