JEE Mains · Physics · STD 12 - 2. Electric potential and capacitance
Three charges \(Q, +q\) and \(+q\) are placed at the vertices of a right -angle isosceles triangle as shown below. The net electrostatic energy of the configuration is zero, if the value of \(Q\) is
- A \(+q\)
- B \(\frac{{ - \sqrt 2 q}}{{\sqrt 2 + 1}}\)
- C \(\frac{{ - q}}{{1 + \sqrt 2 }}\)
- D \(-2q\)
Answer & Solution
Correct Answer
(B) \(\frac{{ - \sqrt 2 q}}{{\sqrt 2 + 1}}\)
Step-by-step Solution
Detailed explanation
\(\mathrm{U}_{\text {Total }}=\frac{\mathrm{kQq}}{\mathrm{a}}+\frac{\mathrm{kq}^{2}}{\mathrm{a}}+\frac{\mathrm{kQq}}{\mathrm{a} \sqrt{2}}=0\) \(\Rightarrow Q=\frac{-q}{\left(1+\frac{1}{\sqrt{2}}\right)}\)
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 cell \(E _{1}\) of \(emf 6 V\) and internal resistance \(2 \Omega\) is connected with another cell \(E _{2}\) of \(emf 4 V\) and internal resistance \(8 \Omega\) (as shown in the figure). The potential difference across points \(X\) and \(Y\) is............ \(V\)
JEE Mains 2021 Hard - A gas molecule of mass \(M\) at the surface of the Earth has kinetic energy equivalent to \(0\,^oC\). If it were to go up straight without colliding with any other molecules, how high it would rise? Assume that the height attained is much less than radius of the earth. (\(k_B\) is Boltzmann constant)JEE Mains 2014 Medium
- The activity of a radioactive material is \(6.4 \times 10^{-4}\) curie. Its half life is \(5\; days\). The activity will become \(5 \times 10^{-6}\) curie after \(.......day\)JEE Mains 2022 Medium
- For a certain metal, when monochromatic light of wavelength \(\lambda\) is incident, the stopping potential for photoelectrons is \(3V_0\). When the same metal is illuminated by light of wavelength \(2\lambda\), then the stopping potential becomes \(V_0\). The threshold wavelength for photoelectric emission for the given metal is \(\alpha\lambda\). The value of \(\alpha\) is _______.JEE Mains 2026 Medium
- A point charge of magnitude \(+ 1\,\mu C\) is fixed at \((0, 0, 0) \). An isolated uncharged spherical conductor, is fixed with its center at \((4, 0, 0).\) The potential and the induced electric field at the centre of the sphere isJEE Mains 2013 Hard
- A very long wire \(ABDMNDC\) is shown in figure carrying current \(I. AB\) and \(BC\) parts are straight, long and at right angle. At \(D\) wire forms a circular turn \(DMND\) of radius \(R. AB.\) \(\mathrm{BC}\) parts are tangential to circular turn at \(\mathrm{N}\) and \(D\). Magnetic field at the centre of circle is
JEE Mains 2020 Hard
More PYQs from JEE Mains
- Two identical charged particles each having a mass \(10 \,g\) and charge \(2.0 \times 10^{-7}\,C\) area placed on a horizontal table with a separation of \(L\) between then such that they stay in limited equilibrium. If the coefficient of friction between each particle and the table is \(0.25\), find the value of \(L\).[Use \(g =10\,ms ^{-2}\) ]..........\(cm\)JEE Mains 2022 Medium
- The set of all values of \(\lambda \) for which the system of linear equations \(x - 2y - 2z = \lambda x\) ; \(x + 2y + z = \lambda y\) ; \(-x - y = \lambda z\) has non zero solutions.JEE Mains 2019 Hard
- The value of the resistor, \(R_S\), needed in the \(dc\) voltage regulator circuit shown here, equals
JEE Mains 2015 Medium - The centre of a circle C is at the centre of the ellipse \(E: \frac{x^2}{a^2}+\frac{y^2}{b^2}=1, a \gt b\). Let \(C\) pass through the foci \(F_1\) and \(F_2\) of \(E\) such that the circle \(C\) and the ellipse \(E\) intersect at four points. Let P be one of these four points. If the area of the triangle \(\mathrm{PF}_1 \mathrm{~F}_2\) is 30 and the length of the major axis of E is 17 , then the distance between the foci of E is :JEE Mains 2025 Easy
- Consider three observations \(a, b\) and \(c\) such that \(b = a + c .\) If the standard deviation of \(a +2\) \(b +2, c +2\) is \(d ,\) then which of the following is true ?JEE Mains 2021 Medium
- A radioactive element \({ }_{92}^{242} X\) emits two \(\alpha\)-particles, one electron and two positrons. The product nucleus is represented by \({ }_{ P }^{234} Y\). The value of \(P\) is \(..................\)JEE Mains 2023 Medium