JEE Mains · Physics · STD 12 - 3. current electricity
When a potential difference \(V\) is applied across a wire of resistance \(R\), it dissipates energy at a rate \(W\). If the wire is cut into two halves and these halves are connected mutually parallel across the same supply, the same supply, the energy dissipation rate will become what?
- A \(1 / 4 \mathrm{~W}\)
- B \(1 / 2 \mathrm{~W}\)
- C \(2 \mathrm{~W}\)
- D \(4 \mathrm{~W}\)
Answer & Solution
Correct Answer
(D) \(4 \mathrm{~W}\)
Step-by-step Solution
Detailed explanation
\( \frac{\mathrm{v}^2}{\mathrm{R}}=\mathrm{W}\) \(....(i)\) \(\frac{\mathrm{v}^2}{\frac{1}{2}\left(\frac{\mathrm{R}}{2}\right)}=\mathrm{W}^{\prime}\) \(...(ii)\) From \((i)\)&\((ii)\), we get \(W^{\prime}=4 W\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- A solid sphere of mass \(M\) and radius \(R\) is divided into two unequal parts. The smaller part having mass \(M/8\) is converted into a sphere of radius \(r\) and the larger part is converted into a circular disc of thickness \(t\) and radius \(2R\). If \(I_1\) is moment of inertia of a sphere having radius \(r\) about an axis through its centre and \(I_2\) is the moment of inertia of a disc about its diameter, the ratio of their moment of inertia \(I_2/I_1 = \) _____.JEE Mains 2026 Hard
- A plane electromagnetic wave of frequency \(500\, MHz\) is travelling in vacuum along \(y-\)direction. At a particular point in space and time, \(\overrightarrow{ B }=8.0 \times 10^{-8} \hat{ z } \;T\). The value of electric field at this point is (speed of light \(\left.=3 \times 10^{8}\, ms ^{-1}\right)\) \(\hat{ x }, \hat{ y }, \hat{ z }\) are unit vectors along \(x , y\) and \(z\) direction.JEE Mains 2021 Medium
- The kinetic energy of translation of the molecules in 50 g of \(\mathrm{CO}_2\) gas at \(17^{\circ} \mathrm{C}\) isJEE Mains 2025 Easy
- In a series \(L R\) circuit with \(X_L=R\). power factor is \(P_1\). If a capacitor of capacitance \(C\) with \(X _{ C }= X _{ L }\) is added to the circuit the power factor becomes \(P _2\). The ratio of \(P_1\) to \(P_2\) will be :JEE Mains 2023 Medium
- The position vector of the centre of mass \(\vec r\, cm\) of an asymmetric uniform bar of negligible area of cross-section as shown in figure is
JEE Mains 2019 Medium - Consider the \(LR\) circuit shown in the figure. If the switch \(S\) is closed at \(t = 0\) then the amount of charge that passes through the battery between \(t = 0\) and \(t = \frac{L}{R}\) is
JEE Mains 2019 Hard
More PYQs from JEE Mains
- Let \(P\) be the point of intersection of the common tangents to the parabola \(y^2 = 12x\) and the hyperbola \(8x^2 -y^2 = 8\). If \(S\) and \(S'\) denote the foci of the hyperbola where \(S\) lies on the positive \(x-\) axis then \(P\) divides \(SS'\) in a ratioJEE Mains 2019 Hard
- Three harmonic waves having equal frequency \(\mathrm{v}\) and same intensity \(\mathrm{I}_{0}\), have phase angles \(0 , \frac{\pi}{4}\) and \(-\frac{\pi}{4}\) respectively. When they are superimposed the intensity of the resultant wave is close toJEE Mains 2020 Medium
- Let \(p,q\in R.\) if \(2-\sqrt 3\) is a root of the quadratic equation, \(x^2 + px + q = 0,\) thenJEE Mains 2019 Hard
- If the shortest distance between the lines \(\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{\lambda}\) and \(\frac{x-2}{1}=\frac{y-4}{4}=\frac{z-5}{5}\) is \(\frac{1}{\sqrt{3}}\), then the sum of all possible values of \(\lambda\) isJEE Mains 2022 Medium
- A parallel beam of light is allowed to fall on a transparent spherical globe of diameter \(30 \,cm\) and refractive index \(1.5\). The distance from the centre of the globe at which the beam of light can converge is________ \(mm\)JEE Mains 2022 Hard
- A heavy iron bar of weight \(12 \mathrm{~kg}\) is having its one end on the ground and the other on the shoulder of a man. The rod makes an angle \(60^{\circ}\) with the horizontal, the weight experienced by the man is :JEE Mains 2024 Hard