Q.81 Which of the following statements about the law of illumination is correct?Ans 1. The illumination is directly proportional to the square luminous intensity and inversely proportional to the distance of the surface from the source.2. The illumination ...

Q.67 The capacitance per kilometre of 3-phase belted cable is 0.09 F between the two cores with the third core connected to the lead sheath. Determine the core to neutral capacitance for the 5 km long cable.Ans 1. ...

Q.89Ans 1. infinite2. 10 Ω3. zero4. 0.1 ΩCorrect Ans: 1

Q.69 An electric current of 10 A is divided into three branches named branch1, branch2 and branch3, respectively, the lengths of the wires in the three branches being proportional to 1, 2 and 4. If wires of the ...

Q.65 In a pure inductive circuit if the supply frequency is reduced to 1/10th of the previous value, the current will be:Ans 1. the same2. ten times high3. reduced by one tenth4. reduced to one tenthCorrect Ans: 2

Q.57 What is the SI unit of permeability?Ans 1. Henry per meter2. Ampere – meter3. Weber per meter4. Ohm – meterCorrect Ans: 1

Q.76 Earth resistance does NOT depend on ________.Ans 1. nature of the soil2. content of iron3. salt content in the soil4. neutral earthingCorrect Ans: 4

Q.82 The barrier voltage for germanium is _____________ at 25°C.Ans 1. infinity2. 0.3 V3. 0 V4. 0.7 VCorrect Ans: 2

Q.59 A 200 V lamp has a total flux of 1000 lumens and takes a current of 0.5 A. Calculate its luminous efficiency?Ans 1. 5 lumens/watt2. 10 lumens/watt3. 4 lumens/watt4. 1 lumen/wattCorrect Ans: 2

Q.58 In lighting, standard reflectors are made to accommodate lamps of rating from ________.Ans 1. 50 to 1200 watts2. 20 to 1000 watts3. 40 to 1500 watts4. 80 to 2000 wattsCorrect Ans: 3