| ⇦ | 
| ⇨ |
The identical cells connected in series are needed to heat a wire of length one meter and radius ‘r’ by 10⁰C in time ‘t’. How many cells will be required to heat the wire of length two meter of the same radius by the same temperature in time ‘t’?
Options
(a) 10
(b) 20
(c) 30
(d) 40
Correct Answer:
20
Explanation:
Resistance is directly proportional to length of the wire. As length is doubled so mass is doubled and resistance is doubled. We have
(10 E)² / R . t = mS∆T,
Now, (nE)²t / 2R = (2m) S∆T
⇒ n²E²t / 2R = 2 . 10²E²t / R
⇒ n = 20
Related Questions: - A proton beam enters a magnetic field of 10⁻⁴ Wb/m² normally. If the specific charge
- A satellite is revolving around the earth with a kinetic energy E. The minimum
- The maximum particle velocity in a wave motion is half the wave velocity.
- A toroid having 200 turns carries a current of 1 A. The average radius of the toroid
- Slope of PV and V for an isobaric process will be
Topics: Current Electricity
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- A proton beam enters a magnetic field of 10⁻⁴ Wb/m² normally. If the specific charge
- A satellite is revolving around the earth with a kinetic energy E. The minimum
- The maximum particle velocity in a wave motion is half the wave velocity.
- A toroid having 200 turns carries a current of 1 A. The average radius of the toroid
- Slope of PV and V for an isobaric process will be
Topics: Current Electricity (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
18000+ students are using NEETLab to improve their score. What about you?
Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.
Share this page with your friends
Leave a Reply