JEE Mains · Physics · STD 12 - 3. current electricity
The ratio of the equivalent resistance of the network (shown in figure) between the points \(a\) and \({b}\) when switch is open and switch is closed is \({x}: 8 .\) The value of \({x}\) is ..... .
- A \(11\)
- B \(9\)
- C \(10\)
- D \(8\)
Answer & Solution
Correct Answer
(B) \(9\)
Step-by-step Solution
Detailed explanation
\(R_{e q \text { open }}=\frac{3 R}{2}\) \(R_{e q \text { closed }}=2 \times \frac{R \times 2 R}{3 R}=\frac{4 R}{3}\) \(\frac{{R}_{\text {eq open }}}{{R}_{\text {eq closed }}}=\frac{3 R}{2} \times \frac{3}{4 {R}}=\frac{9}{8}\) \(\therefore \quad {X}=9\)
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 horizontal straight wire \(5 \mathrm{~m}\) long extending from east to west falling freely at right angle to horizontal component of earth's magnetic field \(0.60 \times 10^{-4} \ \mathrm{Wbm}^{-2}\). The instantaneous value of emf induced in the wire when its velocity is \(10 \mathrm{~ms}^{-1}\) is _______ \(\times 10^{-3} \mathrm{~V}\)JEE Mains 2024 Hard
- In an experiment, a set of reading are obtained \(-1.24 mm, 1.25 mm, 1.23 mm, 1.21 mm\). The expected least count of the instrument used in recording these readings is ___________ mm.JEE Mains 2026 Medium
- The time taken for the magnetic energy to reach \(25\, \%\) of its maximum value, when a solenoid of resistance \(R ,\) inductance \(L\) is connected to a battery, is :JEE Mains 2021 Hard
- A rubber ball is released from a height of \(5\, m\) above the floor. It bounces back repeatedly, always rising to \(\frac{81}{100}\) of the height through which it falls. Find the average speed of the ball. (Take \(g =10 ms ^{-2}\) ) (in \(ms ^{-1}\))JEE Mains 2021 Hard
- A physical quantity \(p\) is described by the relation \(p\, = a^{1/2}\, b^2\, c^3\, d^{-4}\) If the relative errors in the measurement of \(a, b, c\) and \(d\) respectively, are \(2\% , 1\%, 3\%\) and \(5\%\), then the relative error in \(P\) will be ........... \(\%\)JEE Mains 2017 Medium
- A series \(L-R\) circuit is connected to a battery of emf \(V\). If the circuit is switched on at \(t =0\), then the time at which the energy stored in the inductor reaches \(\left(\frac{1}{n}\right)\) times of its maximum value, isJEE Mains 2020 Hard
More PYQs from JEE Mains
- Three point particles of masses \(1.0\; \mathrm{kg} .1 .5 \;\mathrm{kg}\) and \(2.5\; kg\) are placed at three comers of a right angle triangle of sides \(4.0\; \mathrm{cm}, 3.0 \;\mathrm{cm}\) and \(5.0\; \mathrm{cm}\) as shown in the figure. The center of mass of the system is at a point
JEE Mains 2020 Medium - Three capacitors of capacitances \(25 \mu \mathrm{F}, 30 \mu \mathrm{F}\) and \(45 \mu \mathrm{F}\) are connected in parallel to a supply of \(100\) \(V\). Energy stored in the above combination is \(\mathrm{E}\). When these capacitors are connected in series to the same supply, the stored energy is \(\frac{9}{\mathrm{x}} \mathrm{E}\). The value of \(x\) is _______.JEE Mains 2024 Hard
- If \( z=\frac{\sqrt{3}}{2}+\frac{i}{2}, i=\sqrt{-1} \), then \( (z^{201}-i)^{8} \) is equal to:JEE Mains 2026 Easy
- \(n\) mole a perfect gas undergoes a cyclic process \(ABCA\) (see figure) consisting of the following processes. \(A \rightarrow B :\) Isothermal expansion at temperature \(T\) so that the volume is doubled from \(V _{1}\) to \(V _{2}=2 V _{1}\) and pressure changes from \(P _{1}\) to \(P _{2}\) \(B \rightarrow C :\) Isobaric compression at pressure \(P _{2}\) to initial volume \(V _{1}\) \(C \rightarrow A\) : Isochoric change leading to change of pressure from \(P _{2}\) to \(P _{1}\) Total workdone in the complete cycle \(ABCA\) is
JEE Mains 2021 Hard - Two identical strings \(X\) and \(Z\) made of same material have tension \(T _{ x }\) and \(T _{ z }\) in them. If their fundamental frequencies are \(450\, Hz\) and \(300\, Hz ,\) respectively, then the ratio \(T _{ x } / T _{ z }\) is\(.....\)JEE Mains 2020 Easy
- The frequency of revolution of the electron in Bohr's orbit varies with \(n\), the principal quantum number as _______.JEE Mains 2025 Easy