| ⇦ | 
| ⇨ |
An isolated sphere has a capacitance of 50pF. What would be the radius of the sphere?
Options
(a) 90cm
(b) 45cm
(c) 11.50cm
(d) 5.75cm
Correct Answer:
45cm
Explanation:
As potential of spherical charge (Q) having radius r is given by V = (1 / 4πε₀) (Q / r)
Also, capacitance, C = Q / V = Q / { (1 / 4πε₀) (Q / r)} C = 4πε₀r
If C = 50 × 10⁻¹² F, then
Radius of the sphere r = 50 × 10⁻¹² / 4πε₀
= 50 × 10⁻¹² × 9 × 10⁹
= 50 × 9 × 10⁻³
= 450 × 10⁻³ m
= 0.450 m = 45 cm
Related Questions: - What is the energy of photon whose wavelength is 6840 Å?
- The ionisation energy of an electron in the ground state of helium atom is 24.6 eV.
- The difference in the lengths of a mean solar day and a sidereal day is about
- Two coils of self inductance 2 mH and 8 mH are placed so close together
- For photoelectric emission from certain metal the cut-off frequency is v
Topics: Electrostatics
(146)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- What is the energy of photon whose wavelength is 6840 Å?
- The ionisation energy of an electron in the ground state of helium atom is 24.6 eV.
- The difference in the lengths of a mean solar day and a sidereal day is about
- Two coils of self inductance 2 mH and 8 mH are placed so close together
- For photoelectric emission from certain metal the cut-off frequency is v
Topics: Electrostatics (146)
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
As Capacitance of Isolated sphere =4π€R
Given,
C=50picofarad
Then,
50×10(power -12)= 1/9×10(power9)×R
R=0.45m or 45cm….