Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEET2023PhysicsCurrent ElectricityActual

A certain wire A has resistance 81 . The resistance of another wire B of same material and equal length but of diameter thrice the diameter of A will be

Options

  1. A729
  2. B243
  3. C81
  4. D9

Correct answer

D. 9

Step-by-step solution

We know that, R= l A , where A= 4 d^2 aligned & 81= I 4 d^2 , also, R^ = I 4 (3 d)^2 = l 4 9 d^2 & R^ = R 9 = 81 9 =9 aligned

Practice Current Electricity on Quantrex Academy →

More from Current Electricity

A potentiometer wire of 400 cm length has a resistance of 20 . It is connected in series with a resistance of 15 and a accumulator of EMF 6 V (negligible internal resistance). The 2026In the following figure current I equal to 2026The range of voltmeter is 10 V and its resistance is 50 . To convert it to a voltmeter of range 15 V , how much resistance is to be added? 2026When a galvanometer is shunted with a 2 resistance, the deflection is reduced to one-fourth. If the galvanometer is further shunted with a 1 resistance, the further reduction in de 2026A galvanometer can be converted into a voltmeter of certain range by connecting a resistance of 990 in series with it. When the resistance of 480 is connected in series, the range 2026A resistance is to be measured using a meter bridge; the student chooses the standard resistance R to be 100 . The student finds the null point at l₁=16 cm. To get the null point n 2026Which of the following statements is FALSE? A. In a balanced Wheatstone bridge, if the cell and the galvanometer are exchanged, the null point is disturbed. B. A rheostat can be us 2026A potentiometer wire has length 4 m and resistance 8 . The resistance that must be connected in series with the wire and the driving battery of e.m.f. 2 V, so as to get a potential 2026 Full Current Electricity list All NEET PYQs