| ⇦ | 
| ⇨ |
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: - An object is projected with a velocity of 20 m/s making an angle of 45⁰ with horizontal.
- Length of a conductor is 50 cm radius of cross section 0.1 cm and resistivity
- Electrons with energy 80 keV are incident on the tungsten target of an X-ray tube.
- A current I flows along the length of an infinitely long, straight, thin walled pipe.
- A layer of glycerine of thickness 1 mm present between a large surface area of 0.1 m².
Topics: Electrostatics
(146)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- An object is projected with a velocity of 20 m/s making an angle of 45⁰ with horizontal.
- Length of a conductor is 50 cm radius of cross section 0.1 cm and resistivity
- Electrons with energy 80 keV are incident on the tungsten target of an X-ray tube.
- A current I flows along the length of an infinitely long, straight, thin walled pipe.
- A layer of glycerine of thickness 1 mm present between a large surface area of 0.1 m².
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….