JEE Mains · Physics · STD 12 - 3. current electricity
A heater is designed to operate with a power of \(1000 \mathrm{~W}\) in a \(100 \mathrm{~V}\) line. It is connected in combination with a resistance of \(10 \Omega\) and a resistance \(R\), to a \(100 \mathrm{~V}\) mains as shown in figure. For the heater to operate at \(62.5 \mathrm{~W}\), the value of \(\mathrm{R}\) should be _______ \(\Omega\).
- A \(7\)
- B \(9\)
- C \(3\)
- D \(5\)
Answer & Solution
Correct Answer
(D) \(5\)
Step-by-step Solution
Detailed explanation
\(R_{\text {heater }}=\frac{V^2}{P}=\frac{(100)^2}{1000}=10 \Omega\) For heater \(P=\frac{V^2}{R} \Rightarrow V=\sqrt{P R}\) \(\mathrm{V}=\sqrt{62.5 \times 10}\) \(\mathrm{~V}=25 \mathrm{v}\) (Image) \(i_1=\frac{75}{10}=7.5 A, i_H=\frac{25}{10}=2.5 A\) \(i_R=i_1-i_H=5\)…
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
- The temperature of \(3.00\, {mol}\) of an ideal diatomic gas is increased by \(40.0^{\circ} {C}\) without changing the pressure of the gas. The molecules in the gas rotate but do not oscillate. If the ratio of change in internal energy of the gas to the amount of workdone by the gas is \(\frac{{x}}{10} .\) Then the value of \({x}\) (round off to the nearest integer) is ..... . \(\left(\right.\) Given \(\left.{R}=8.31\, {J} {mol}^{-1} {K}^{-1}\right)\)JEE Mains 2021 Medium
- The resistances of the platinum wire of a platinum resistance thermometer at the ice point and steam point are \(8 \Omega\) and \(10 \Omega\) respectively. After inserting in a hot bath of temperature \(400^{\circ} \mathrm{C}\), the resistance of platinum wire is _______.JEE Mains 2024 Hard
- Two identical capacitors \(\mathrm{A}\) and \(\mathrm{B}\), charged to the same potential \(5\; \mathrm{V}\) are connected in two different circuits as shown below at time \(\mathrm{t}=0\) If the charge on capacitors \(A\) and \(B\) at time \(\mathrm{t}=\mathrm{CR}\) is \(\mathrm{Q}_{\mathrm{A}}\) and \(\mathrm{Q}_{\mathrm{B}}\) respectively, then (Here \(e\) is the base of natural logarithm)
JEE Mains 2020 Medium - A train starting from rest first accelerates uniformly up to a speed of \(80 \mathrm{~km} / \mathrm{h}\) for time \(t\), then it moves with a constant speed for time 3t. The average speed of the train for this duration of journey will be (in \(\mathrm{km} / \mathrm{h}\) ) _______.JEE Mains 2024 Hard
- A small spherical ball of radius \(r\), falling through a viscous medium of negligible density has terminal velocity ' \(v\) '. Another ball of the same mass but of radius \(2 r\), falling through the same viscous medium will have terminal velocity _______.JEE Mains 2024 Hard
- A source and a detector move away from each other in absence of wind with a speed of \(20\, {m} / {s}\) with respect to the ground. If the detector detects a frequency of \(1800\, {Hz}\) of the sound coming from the source, then the original frequency of source considering speed of sound in air \(340\, {m} / {s}\) will be \({Hz}\)JEE Mains 2021 Easy
More PYQs from JEE Mains
- The mean and variance of \(8\) observations are \(10\) and \(13.5,\) respectively. If \(6\) of these observations are \(5,7,10,12,14,15,\) then the absolute difference of the remaining two observations isJEE Mains 2020 Hard
- A light string passing over a smooth light fixed pulley connects two blocks of masses \(m_1\) and \(m_2\). If the acceleration of the system is \(g / 8\), then the ratio of masses is _______.
JEE Mains 2024 Hard - The curve satisfying the differential equation, \((x^2 -y^2) \,dx + 2xydy\, = 0\) and passing through the point \((1 , 1 )\) isJEE Mains 2019 Hard
- A planet revolving in elliptical orbit has \((A)\) a constant velocity of revolution. \((B)\) has the least velocity when it is nearest to the sun. \((C)\) its areal velocity is directly proportional to its velocity. \((D)\) areal velocity is inversely proportional to its velocity. \((E)\) to follow a trajectory such that the areal velocity is constant. Choose the correct answer from the options given belowJEE Mains 2021 Hard
- The real valued function \(f(x)=\frac{\operatorname{cosec}^{-1} x}{\sqrt{x-[x]}, \text { where }}\) \([ x ]\) denotes the greatest integer less than or equal to \(x,\) is defined for all \(x\) belonging toJEE Mains 2021 Hard
- Let \(\alpha, \alpha + 2, \alpha \in \mathbb{Z}\), be the roots of the quadratic equation \(x(x+2) + (x+1)(x+3) + (x+2)(x+4) + \ldots + (x+n-1)(x+n+1) = 4n\) for some \(n \in \mathbb{N}\). Then \(n + \alpha\) is equal to :JEE Mains 2026 Hard