MODULE 3 CHAPTER 3 QUIZ 4

Question Number. 31. The property of a material to accept lines of flux is called.

Option A. retentivity.

Option B. reluctance.

Option C. permeability.

Correct Answer is. permeability. Explanation. NIL .................................

.Question Number. 32. Magnetomotive force can be found by.

Option A. I * N. Option B. Blv.

Option C. N/I.

Correct Answer is. I * N. Explanation. MMF (symbol H) = amps * turns (units are ampere turns) ..................................

Question Number. 33. When a conductor is cut by magnetic lines of force an EMF is induced. This is. Option A. Kirkchoff's Law. Option B. Faraday's Law. Option C. Lenz's Law. Correct Answer is. Faraday's Law. Explanation. Faraday's Law is induced EMF is directly proportional to the rate of change of flux ..................................

Question Number. 34. The direction of induced conventional current in a wire rotating in a magnetic field can be determined by.

Option A. cork screw rule.

Option B. Fleming's right hand rule.

Option C. Fleming's left hand rule.

Correct Answer is. Fleming's right hand rule.

Explanation. NIL ..................................

Question Number. 35. How would you find the direction of the electron flow in an armature located in a magnetic field?.

Option A. Flemings left hand rule.

Option B. Flemings right hand rule.

Option C. Maxwells corkscrew rule.

Correct Answer is. Flemings left hand rule.

Explanation. Assuming conventional current flow ..................................

Question Number. 36. What is the SI unit of conductance?.

Option A. Ohm. Option B. Siemen.

Option C. Ohm-metre.

Correct Answer is. Siemen. ..

. Explanation. Conductance is 1/R and is measured in Siemens ..................................

Question Number. 37. What is the SI unit of resistivity?

. Option A. Ohms.

Option B. Ohm metre.

Option C. Ohms/metre.

Correct Answer is. Ohm metre.

Explanation. Resistivity is ohm metre (transpose the resistance formula R = ρL / A, and see what units it gives) ..................................

Question Number. 38. What is the formula for conductance? (R=Resistance). Option A. R + 1. Option B. 1/R. Option C. 1-R. Correct Answer is. 1/R. Explanation. Conductance is the inverse of resistance ..................................

Question Number. 39. In electrical circuit, Direct Current power is represented by the.

Option A. Ampere. Option B. Watt.

Option C. Joule.

Correct Answer is. Watt.

Explanation. DC power is measured in Watts .................................

.Question Number. 40. In S.I. units, work is denoted by.

Option A. Newton-meter which is Joules.

Option B. Joules/sec which is Watts.

Option C. Kilogram-force-meter/sec which is Metric Horsepower.

Correct Answer is. Newton-meter which is Joules.

Explanation. Work has the same unit as energy, i.e. Nm or Joule ..................................