JEE Mains · Physics · STD 12 - 1. Electric charges and fields
A point charge +q is placed at the origin. A second point charge +9 q is placed at \((\mathrm{d}, 0,0)\) in Cartesian coordinate system. The point in between them where the electric field vanishes is :
- A \((4 \mathrm{~d} / 3,0,0)\)
- B \((\mathrm{d} / 4,0,0)\)
- C \((3 \mathrm{~d} / 4,0,0)\)
- D \((\mathrm{d} / 3,0,0)\)
Answer & Solution
Correct Answer
(B) \((\mathrm{d} / 4,0,0)\)
Step-by-step Solution
Detailed explanation
Let \(\mathrm{E}_{\mathrm{p}}=0\) \(\begin{aligned} & \therefore \frac{\mathrm{kq}}{\mathrm{x}^2}=\frac{\mathrm{k} 9 \mathrm{q}}{(\mathrm{~d}-\mathrm{x})^2} \\ & \Rightarrow \frac{\mathrm{~d}-\mathrm{x}}{\mathrm{x}}=3 \Rightarrow \mathrm{x}=\frac{\mathrm{d}}{4} \end{aligned}\)…
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 body of mass \(1000 \mathrm{~kg}\) is moving horizontally with a velocity \(6 \mathrm{~m} / \mathrm{s}\). If \(200 \mathrm{~kg}\) extra mass is added, the final velocity (in \(\mathrm{m} / \mathrm{s}\) ) is:JEE Mains 2024 Hard
- Two particles \(\mathrm{X}\) and \(\mathrm{Y}\) having equal charges are being accelerated through the same potential difference. Thereafter they enter normally in a region of uniform magnetic field and describes circular paths of radius \(R_1\) and \(R_2\) respectively. The mass ratio of \(\mathrm{X}\) and \(\mathrm{Y}\) is _______.JEE Mains 2024 Medium
- A travelling microscope is used to determine the refractive index of a glass slab. If \(40\) divisions are there in \(1 \; cm\) on main scale and \(50\) Vernier scale divisions are equal to \(49\) main scale divisions, then least count of the travelling microscope is \(\dots \; \times 10^{-6} \; m\)JEE Mains 2022 Medium
- A block of mass \(40 \,kg\) slides over a surface, when a mass of \(4 \,kg\) is suspended through an inextensible massless string passing over frictionless pulley as shown below. The coefficient of kinetic friction between the surface and block is \(0.02\). The acceleration of block is ............ \(ms ^{-2}\) (Given \(g =10 \,ms ^{-2}\).)
JEE Mains 2022 Medium - Modern vacuum pumps can evacuate a vessel down to a pressure of \(4.0 \times {10^{ - 15}}\, atm\) at room temperature \((300\, K)\). Taking \(R = 8.0\, JK^{-1}\, mole^{-1}\) , \(1\, atm = 10^5\, Pa\) and \(N_ {Avogadro} = 6 \times 10^{23}\, mole^{-1}\) , the mean distance between molecules of gas in an evacuated vessel will be of the order ofJEE Mains 2014 Medium
- A metal rod of length \(L\) rotates about one end at origin with a uniform angular velocity \(\omega\). The magnetic field radially falls off as \(B(r) = B_0 e^{-\lambda r}\); \(\lambda\) being a positive constant. The emf induced (neglecting the centripetal force on electrons in the rod) is :JEE Mains 2026 Hard
More PYQs from JEE Mains
- Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In an insulated container, a gas is adiabatically shrunk to half of its initial volume. The temperature of the gas decreases.
Reason (R): Free expansion of an ideal gas is an irreversible and an adiabatic process.
In the light of the above statements, choose the correct answer from the options given below :JEE Mains 2025 Easy - Let the plane \(P: \vec{r} \cdot \vec{a}=d\) contain the line of intersection of two planes \(\overrightarrow{ r } \cdot(\hat{ i }+3 \hat{ j }-\hat{ k })=6\) and \(\overrightarrow{ r } \cdot(-6 \hat{ i }+5 \hat{ j }-\hat{ k })=7\). If the plane \(P\) passes through the point \(\left(2,3, \frac{1}{2}\right)\), then the value of \(\frac{|13 \vec{a}|^{2}}{ d ^{2}}\) is equal toJEE Mains 2022 Hard
- If the set \(R=\{(a, b) ; a+5 b=42, a, b \in \mathbb{N}\}\) has \(m\) elements and \(\sum_{n=1}^m\left(1-i^{n !}\right)=x+i y\), where \(I=\sqrt{-1}\), then the value of \(m+x+y\) is :JEE Mains 2024 Hard
- If \(\alpha = \displaystyle\int_0^{2\sqrt{3}} \log_2(x^2 + 4)\,dx + \displaystyle\int_2^4 \sqrt{2^x - 4}\,dx\), then \(\alpha^2\) is equal to _______.JEE Mains 2026 Hard
- Let \(S = \{\theta \in (-2\pi, 2\pi) : \cos\theta + 1 = \sqrt{3}\sin\theta\}\). Then \(\sum_{\theta \in S}\theta\) is equal to:JEE Mains 2026 Medium
- Let \(A=\left[\begin{array}{ccc}2 & 2+p & 2+p+q \\ 4 & 6+2 p & 8+3 p+2 q \\ 6 & 12+3 p & 20+6 p+3 q\end{array}\right]\).
If \(\operatorname{det}(\operatorname{adj}(\operatorname{adj}(3 \mathrm{~A})))=2^{\mathrm{m}} \cdot 3^{\mathrm{n}}, \mathrm{m}, \mathrm{n} \in \mathrm{N}\), then \(\mathrm{m}+\mathrm{n}\) is equal toJEE Mains 2025 Medium