Electric Charges and Fields - Online Test
Q1. Gauss's law states that
Answer : Option D
Explaination / Solution:
Gauss Theorem--- According to Gauss theorem the electric flux through a closed surface is given by times
Q2.
An electric dipole in an electric field experiences a torque
Answer : Option C
Explaination / Solution:
= pE Sinθ OR =× , the direction of torque or the direction of rotation of dipole is given by right hand palm rule or by Maxwell screw rule.
Q3. For an Infinite thin plane sheet of uniform surface charge density The magnitude of is
Answer : Option C
Explaination / Solution:
Electric field due to thin sheet— Let a thin sheet on which a charge q is distributed uniformly , let the Gaussian surface on both sides is in form of cylinder as shown in figure
(left) + (right)=$ =EA Cos0+EA Cos0=2EA
(left) + (right)=$ =EA Cos0+EA Cos0=2EA
Q4. An electric field can deflect
Answer : Option D
Explaination / Solution:
Only alpha rays are moving with small velocity and having charge so they will be affected by electric field.
Q5. A conducting sphere of radius 5 cm is charged to 15 μ C. Another uncharged sphere of radius 10 cm is allowed to touch it for enough time. After the two are separated, the surface density of charge on the two spheres will be in the ratio
Answer : Option A
Explaination / Solution:
Q6. A Gaussian sphere encloses an electric dipole within it. Total flux across the sphere is
Answer : Option D
Explaination / Solution:
Q7. A cylinder of radius R and length L is placed in an uniform electric field E parallel to the cylinder axis. The total flux for the surface of the cylinder is given by
Answer : Option B
Explaination / Solution:
Incoming flux =outgoing flux so net flux=0
Q8. When a negatively charged conductor is connected to earth,
Answer : Option A
Explaination / Solution:
After earthing a positively charged conductor electrons flow from earth to conductor and if a negatively charged conductor is earthed then electrons flows from conductor to earth.
Q9. An uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force look like
Answer : Option C
Explaination / Solution:
Electric lines of force never intersect the conductor. They are perpendicular and slightly curved near the surface of conductor.so answer is A
Q10. A hollow spherical conductor of radius 2m carries a charge of 500 μ C. Then electric field strength at its surface is
Answer : Option D
Explaination / Solution:
