JEE Mains · Physics · STD 12 - 2. Electric potential and capacitance
If the charge on a capacitor is increased by \(2C\), the energy stored in it increases by \(44 \%\). The original charge on the capacitor is (in \(C\) )
- A \(10\)
- B \(20\)
- C \(30\)
- D \(40\)
Answer & Solution
Correct Answer
(A) \(10\)
Step-by-step Solution
Detailed explanation
\(U \propto q ^{2}\) \(\Rightarrow q _{ f }=1.2 \,q\) \(q _{ f }- q =2\) \(\Rightarrow 1.2 \,q - q =2\) \(q =10\)
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
- Each side of a box made of metal sheet in cubic shape is \('a'\) at room temperature \('T'\), the coefficient of linear expansion of the metal sheet is \(^{\prime} \alpha^{\prime}\). The metal sheet is heated uniformly, by a small temperature \(\Delta T\), so that its new temperature is \(T +\Delta T\). Calculate the increase in the volume of the metal box.JEE Mains 2021 Medium
- A river is flowing from west to east direction with speed of \(9 \mathrm{~km} \mathrm{~h}^{-1}\). If a boat capable of moving at a maximum speed of \(27 \mathrm{~km} \mathrm{~h}^{-1}\) in still water, crosses the river in half a minute, while moving with maximum speed at an angle of \(150^{\circ}\) to direction of river flow, then the width of the river is :JEE Mains 2025 Easy
- Match List \(I\) with List \(II\) of Electromagnetic waves with corresponding wavelength range :
Choose the correct answer from the options given below:List \(I\) List \(II\) \((A)\) Microwave \((I)\) \(400\,nm\) to \(1\,nm\) \((B)\) Ultraviolet \((II)\) \(1\,nm\) to \(10^{-3}\,nm\) \((C)\) \(X-\)Ray \((III)\) \(1\,mn\) to \(700\,nm\) \((D)\) Infra-red \((IV)\) \(0.1\,m\) to \(1\,mm\) JEE Mains 2023 Medium - A very long (length \(L\) ) cylindrical galaxy is made of uniformly distributed mass and has radius \(R(R < < L).\) A star outside the galaxy is orbiting the galaxy in a plane perpendicular to the galaxy and passing through its centre. If the time period of star is \(T\) and its distance from the galaxy's axis is \(r,\) thenJEE Mains 2015 Medium
- A pulley of radius \(1.5\,m\) is rotated about its axis by a force \(F =\left(12 t -3 t ^{2}\right)\,N\) applied tangentially (while \(t\) is measured in seconds). If moment of inertia of the pulley about its axis of rotation is \(4.5\,kg\,m ^{2}\), the number of rotations made by the pulley before its direction of motion is reversed, will be \(\frac{K}{\pi}\). The value of \(K\) is \(.....\)JEE Mains 2022 Hard
- A ray of light is incident at an angle of \(60^o\) on one face of a prism of angle \(30^o\) . The emergent ray of light makes an angle of \(30^o\) with incident ray. The angle made by the emergent ray with second face of prism will be....\(^o\)JEE Mains 2018 Hard
More PYQs from JEE Mains
- In a school, there are three types of games to be played. Some of the students play two types of games, but none play all the three games. Which Venn diagrams can justify the above statement ?
JEE Mains 2021 Easy - A plane \(P\) contains the line \(x+2 y+3 z+1=0=x-y-z-6\) and is perpendicular to the plane \(-2 x+y+z+8=0\). Then which of the following points lies on \(\mathrm{P}\) ?JEE Mains 2021 Medium
- Define a relation R on the interval \(\left[0, \frac{\pi}{2}\right)\) by \(x \mathrm{R} y\) if and only if \(\sec ^2 x-\tan ^2 y=1\). Then R is :JEE Mains 2025 Easy
- The integral \(\int\left(\left(\frac{x}{2}\right)^x+\left(\frac{2}{x}\right)^x\right) \log _2 x d x\) is equal toJEE Mains 2023 Hard
- If the sum of the first four terms of an A.P. is 6 and the sum of its first six terms is 4, then the sum of its first twelve terms isJEE Mains 2026 Hard
- If the root mean square velocity of hydrogen molecule at a given temperature and pressure is \(2 \mathrm{~km} / \mathrm{s}\), the root mean square velocity of oxygen at the same condition in \(\mathrm{km} / \mathrm{s}\) is _______.JEE Mains 2024 Hard