Question:
A wire when connected to $220\, V$ mains supply has power dissipation $P_1$. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is $P_2 \, then \, P_2 : P_1$ is
A wire when connected to $220\, V$ mains supply has power dissipation $P_1$. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is $P_2 \, then \, P_2 : P_1$ is
Updated On: Jun 23, 2023
- 1
- 4
- 2
- 3
Hide Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
When wire of resistance say R is cut into two pieces, its resistance becomes half i.e. R /2. Here equivalent resistance
$R_{eq} = \frac{1}{2} \frac{R}{2} = \frac{R}{4}$
$\therefore$ $P_2 = \frac{V^2}{R/4} = 4 \frac{V^2}{R} = 4P_1$
or $P_2 : P_1 = 4$
$R_{eq} = \frac{1}{2} \frac{R}{2} = \frac{R}{4}$
$\therefore$ $P_2 = \frac{V^2}{R/4} = 4 \frac{V^2}{R} = 4P_1$
or $P_2 : P_1 = 4$
Was this answer helpful?
0
0
Top Questions on Current electricity
- A uniform metal wire of length \(l\) has 10 Ω resistance. Now this wire is stretched to a length \(2l \) and then bent to form a perfect circle. The equivalent resistance across any arbitrary diameter of that circle is :
- NEET (UG) - 2024
- Physics
- Current electricity
- In an electrical circuit, the voltage is measured as V = (200 ± 4) volt and the current is measured as I = (20 ± 0.2) A. The value of the resistance is:
- NEET (UG) - 2024
- Physics
- Current electricity
- A uniform wire of diameter \(d\) carries a current of \(100 \, \text{mA}\) when the mean drift velocity of electrons in the wire is \(v\). For a wire of diameter \(\frac{d}{2}\) of the same material to carry a current of \(200 \, \text{mA}\), the mean drift velocity of electrons in the wire is
- NEET (UG) - 2024
- Physics
- Current electricity
- In an ammeter, 5% of the main current passes through the galvanometer. If resistance of the galvanometer is G, the resistance of ammeter will be :
- JEE Main - 2024
- Physics
- Current electricity
- A wire of resistance R and radius r is stretched till its radius became r/2. If new resistance of the stretched wire is x R, then value of x is _________.
- JEE Main - 2024
- Physics
- Current electricity
View More Questions
Questions Asked in AMUEEE exam
- The ratio of the half-life time $ (t_{1/2}) $ , to the three quarter life-time, $ (t_{3/4}) $ , for a reaction that is second order
- AMUEEE - 2018
- Order of Reaction
- $ 0.002\, M $ solution of a weak acid has an equivalent conductance $ (\wedge) 60\, ohm^{-1}\, cm^{2}\, eq^{-1} $ . What will be the $ pH $ ? (Given : $ \wedge = 400 \, ohm^{-1} \, cm^{2} \, eq^{-1} $ ]
- AMUEEE - 2018
- Electrochemistry
- The electrode potential, $ E^{\circ} $ , for the reduction of $ MnO^{-}_{4} $ to $ Mn^{2+} $ in acidic medium is $ +1.51\, V $ . Which of the following metal(s) will be oxidised? The reduction reactions and standard electrode potentials for $ Zn^{2+}, Ag^{+} $ , and $ Au^{+} $ are given as $ Zn^{2+} (aq) +2e \to Zn(s), E^{\circ} = -0.762\, V $ $ Ag+ (aq) +e {\rightleftharpoons} Ag (s), E^{\circ}=+0.80 \,V $ $ Au^{+} (aq) +e {\rightleftharpoons} Au(s), E^{\circ}+1.69\,V $
- AMUEEE - 2018
- Electrochemistry
- Three particles, two with masses $ m $ and one with mass $ M $ , might be arranged in any of the four configurations shown below. Rank the configurations according to the magnitude of the gravitational force on $ M $ , least to greatest
- AMUEEE - 2018
- Gravitation
- The $ EAN $ value $ y \left[Ti\left(\sigma-C_{6}H_{5}\right)_{2}\left(\pi-C_{5}H_{5}\right)_{2}\right]^{0} $ is
- AMUEEE - 2018
- coordination compounds
View More Questions
Concepts Used:
Current Electricity
Current electricity is defined as the flow of electrons from one section of the circuit to another.
Types of Current Electricity
There are two types of current electricity as follows:
Direct Current
The current electricity whose direction remains the same is known as direct current. Direct current is defined by the constant flow of electrons from a region of high electron density to a region of low electron density. DC is used in many household appliances and applications that involve a battery.
Alternating Current
The current electricity that is bidirectional and keeps changing the direction of the charge flow is known as alternating current. The bi-directionality is caused by a sinusoidally varying current and voltage that reverses directions, creating a periodic back-and-forth motion for the current. The electrical outlets at our homes and industries are supplied with alternating current.