JEE Mains · Physics · STD 12 - 1. Electric charges and fields
A dipole with two electric charges of \(2 \mu \mathrm{C}\) magnitude each, with separation distance \(0.5 \mu \mathrm{~m}\), is placed between the plates of a capacitor such that its axis is parallel to an electric field established between the plates when a potential difference of 5 V is applied. Separation between the plates is 0.5 mm. If the dipole is rotated by \(30^{\circ}\) from the axis, it tends to realign in the direction due to a torque. The value of torque is :
- A \(5 \times 10^{-9} \mathrm{Nm}\)
- B \(5 \times 10^{-3} \mathrm{Nm}\)
- C \(2.5 \times 10^{-12} \mathrm{Nm}\)
- D \(2.5 \times 10^{-9} \mathrm{Nm}\)
Answer & Solution
Correct Answer
(A) \(5 \times 10^{-9} \mathrm{Nm}\)
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & \mathrm{E}=\frac{\mathrm{v}}{\mathrm{~d}}=\frac{5}{5 \times 10^{-4}}=10^4 \mathrm{~V} / \mathrm{m} \\ & \tau=\mathrm{PE} \sin \theta \end{aligned}\) Where \(\mathrm{P}=\mathrm{qa}=2 \times 10^{-6} \times 5 \times 10^{-7}\)…
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 least count of a screw guage is 0.01 mm . If the pitch is increased by \(75 \%\) and number of divisions on the circular scale is reduced by \(50 \%\), the new least count will be _____ \(\times 10^{-3} \mathrm{~mm}\)JEE Mains 2025 Easy
- Water from a tap emerges vertically downwards with an initial speed of \(1.0\,ms^{-1}.\) The cross-sectional area of the tap is \(10^{-4}\,m^2.\) Assume that the pressure is constant throughout the stream of water and that flow is streamlined. The cross-sectional area of the stream, \(0.15\,m\) below the tap would be: (take \(g = 10\,ms^{-2}\) )JEE Mains 2019 Medium
- The figure gives experimentally measured \(\mathrm{B}\) vs. \(H\) variation in a ferromagnetic material. The retentivity, co-ercivity and saturation. respectively, of the material are
JEE Mains 2020 Medium - An ideal gas undergoes a quasi static, reversible process in which its molar heat capacity \(C\) remains constant. If during this process the relation of pressure \(P\) and volume \(V\) is given by \(PV^n =\) constant, then n is given by (Here \(C_p\) and \(C_v\) are molar specific heat at constant pressure and constant volume, respectively) :JEE Mains 2016 Hard
- The equilateral triangle \(ABC\) is cut from a thin solid sheet of wood. (See figure) \(D, E\) and \(F\) are the mid points of its sides as shown and \(G\) is the centre of the triangle. The moment of inertia of the triangle about an axis passing through \(G\) and perpendicular to the plane of the triangle is \(I_0.\) If the smaller triangle \(DEF\) is removed from \(ABC,\) the moment of inertia of the remaining figure about the same axis is \(I.\) Then
JEE Mains 2019 Hard - Inside a uniform spherical shell \((a)\) the gravitational field is zero \((b)\) the gravitational potential is zero \((c)\) the gravitational field is same everywhere \((d)\) the gravitation potential is same everywhere \((e)\) all of the above Choose the most appropriate answer from the options given belowJEE Mains 2021 Medium
More PYQs from JEE Mains
- For the thin convex lens, the radii of curvature are at \(15 \mathrm{~cm}\) and \(30 \mathrm{~cm}\) respectively. The focal length the lens is \(20 \mathrm{~cm}\). The refractive index of the material is _______.JEE Mains 2024 Hard
- In an \(LCR \) circuit as shown below both switches are open initially. Now switch \(S_1\) is closed, \(S_2\) kept open. ( \(q\) is charge on the capacitor and \(\tau = RC\) is Capacitive time constant). Which of the following statement is correct?
JEE Mains 2013 Medium - The area (in sq. units) of the largest rectangle \(ABCD\) whose vertices \(A\) and \(B\) lie on the \(x\)-axis and vertices \(C\) and \(D\) lie on the parabola, \(y = x ^{2}-1\) below the \(x\) -axis, isJEE Mains 2020 Hard
- A flask contains argon and oxygen in the ratio of \(3: 2\) in mass and the mixture is kept at \(27^{\circ} C\). The ratio of their average kinetic energy per molecule respectively will be ...........JEE Mains 2022 Medium
- Let \(A=I_2-2 \mathrm{MM}^{\mathrm{T}}\), where \(\mathrm{M}\) is real matrix of order \(2 \times 1\) such that the relation \(M^T M=I_1\) holds. If \(\lambda\) is a real number such that the relation \(\mathrm{AX}=\lambda \mathrm{X}\) holds for some non-zero real matrix \(X\) of order \(2 \times 1\), then the sum of squares of all possible values of \(\lambda\) is equal to :JEE Mains 2024 Hard
- The integral \(\int_{\pi /6}^{\pi /3} {{{\sec }^{2/3}}\,x\,\,\cos e{c^{4/3}}\,x\,dx} \) is equal toJEE Mains 2019 Hard