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MCQ
21. What is the resistance-power of an electric iron with 220V and 1100 watt?
11 Ω
33 Ω
22 Ω
44 Ω
22. Which of the following quantites consist of unit as WATT?
force
charge
current
power
ব্যাখ্যা: The St unit of power is the watt and it is discover by the Scottish Engineer James Watt. Power is the rate of consumption of electric energy. So, it is equivalent joules per second.
23. An electric heater is marked 2000W, 200V; the resistance of the coil is--Ω
0.1
20
1/20
200
24. The unit of resistivity is-
Ohms
Ohm/Sqm
Ohm-m
None
25. Resistance depends on:
Cross section
Length
Material
All
26. What is the unit of work?
Newton
Watt
Joule
Pascal
27. Which quantity consists of a unit 1 kWh?
energy
power
time
charge
ব্যাখ্যা: 1 kWh is the amount of energy used by a 1 kW (1000 watt) resistance for 1 hour. Energy = Power x Time
28. Semiconductor-এর temperature coefficient of resistance--
Negative
Zero
Positive
কোনোটিই নয়
ব্যাখ্যা: Semiconductor-এর temperature coefficient of resistance Negative
29. How many 60-watt bulbs will be safe for a home with main meter of 6 amp and 220 volts?
6
10
11
22
30. The minimum dielectric stress in a cable is at-
conductor
surface centre of conductor
lead sheath
none of the above
ব্যাখ্যা: Equation of Resistivity of a wire is- So, resistivity of wire is directly proportional to cross section area (A) and inversly proportional to length (L) of wire.
31. What voltage drop will be there across a 1kW flood light whose resistance when hot is 40 Ω ?
100V
50V
150V
200V
32. Unit of magnetic flux density-
tesla
lux
weber
henry
ব্যাখ্যা: Magnetic Flux density has the dimension mas per time squared electric current. The St derived unit of magnetic flux density is the tesla.
33. SI unit of electrical capacitance--
ohm
farad
henry
coulomb
34. Which one is a semiconductor material?
Phosphorous
Silicon
Rubber
Aluminium
35. 1 coulomb is equal to?
6.24 x 10^18 electron-charge
6.28 x 10^16 electron charge
682 x 10^18 electron charge
6.82 x 10^-18 electron change
36. Energy consumption of a 100-watt bulb for ten hours is
1000kWh
1 unit
100kWh
1kW
37. Unit of electrical energy is:
Newton-meter
Watt-sec
Watt
BTU
38. The resistivity depends upon-
area
material
length
All of these
39. The basic unit of electric charge is-
Ampere-hour
Joule
Coulomb
Newton
40. What type of material is Silicon (Si)?
Conductor
Semiconductor
Insulator
Good conductor