COMEDK · Physics · 19. Current Electricity
The current in a simple series circuit is \(5.0 \mathrm{~A}\).
When an additional resistance of \(2.0 \Omega\) is inserted, the current drops to \(4.0 \mathrm{~A}\). The original resistance of the circuit (in \(\Omega\) ) is
- A 1.25
- B 8
- C 10
- D 20
Answer & Solution
Correct Answer
(B) 8
Step-by-step Solution
Detailed explanation
Given, \(I_{1}=5 \mathrm{~A}, R_{2}=2 \Omega, I_{2}=4 \mathrm{~A}\) Let initial resistance be \(R\). As voltage given is same in both cases, so…
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
- Four masses each 2 kg are placed at the corners A, B, C, D of a mass less square frame. 40 kg mass is at the centre O of a square frame of side 0.2m. It is to be rotated about an axis passing through the centre O and perpendicular to the plane of the frame. Calculate the torque in N-m required to produce an angular acceleration of \(\dfrac{\pi}{2}\ rads^{-2}\).COMEDK 2026 Medium
- The displacement \(x\) (in \(\mathrm{m}\)) of a particle of mass \(\mathrm{m}\) (in \(\mathrm{kg}\) ) moving in one dimension under the action of a force, is related to time \(t\) (in \(\mathrm{s}\)) by \(t=\sqrt{x}+3\). The displacement of the particle when its velocity is zero, will beCOMEDK 2013 Easy
- The temperature of two bodies \(A\) and \(B\) are \(727^{\circ} \mathrm{C}\) and \(327^{\circ} \mathrm{C}\) respectively, the ratio \(H_{A}: H_{B}\) of the rates of heat radiated by them isCOMEDK 2015 Easy
- An LED is constructed from a \(p-n\) junction diode using GaAsP. The energy gap is \(1.9 \mathrm{eV}\). The wavelength of the light emitted will be equal toCOMEDK 2023 Easy
- A string of length \(25 \mathrm{~cm}\) and mass \(10^{-3} \mathrm{~kg}\) is clamped at its ends. The tension in the string is \(2.5 \mathrm{~N}\). The identical wave pulses are generated at one end and at regular interval of time, \(\Delta \mathrm{t}\). The minimum value of \(\Delta \mathrm{t}\), so that a constructive interference takes place between successive pulses isCOMEDK 2024 Medium
- Four charges each with charge \(+q\) are placed at the four corners of a square of side \(l\), a charge \(\frac{-q}{4}\) is at centre of the square. Force on the charge at the centre due to other charges isCOMEDK 2024 Easy
More PYQs from COMEDK
- An important reaction of acetone is auto-condensation in presence of concentrated sulphuric acid to give the aromatic compoundCOMEDK 2013 Hard
- \(A B C\) is a triangle with \(\angle A=30^{\circ}\) and \(B C=10 \mathrm{~cm}\). The area of the circum circle of the triangle is
COMEDK 2020 Hard - A reaction is spontaneous at all temperature, whenCOMEDK 2019 Medium
- The maximum current that can be measured by a galvanometer of resistance \(40 ~\Omega\), is \(10 \mathrm{~mA}\). It is converted into a voltmeter that can read upto \(50 \mathrm{~V}\). The resistance to be connected in series with the galvanometer (in \(\Omega\) ) isCOMEDK 2013 Easy
- Two charges '\(-q\)' each are fixed, separated by distance '\(2 d\)'. A third charge '\(q\)' of mass '\(m\)' placed at the mid-point is displaced slightly by '\(x\)' \((x< < d)\) perpendicular to the line joining the two fixed charges as shown in Fig. The time period of oscillation of '\(q\)' will be
COMEDK 2024 Hard - Photoelectric effect and Raman effect can be explained on the basis ofCOMEDK 2012 Easy