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1.0.0
MCQ
21. 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
22. Semiconductor-এর temperature coefficient of resistance--
Negative
Zero
Positive
কোনোটিই নয়
ব্যাখ্যা: Semiconductor-এর temperature coefficient of resistance Negative
23. An electric heater is marked 2000W, 200V; the resistance of the coil is--Ω
0.1
20
1/20
200
24. The resistivity of the conductor depends on-
area of the conductor
length of the conductor
type of material
none
ব্যাখ্যা: Resistivity depends upon nature of material and physical conditions.
25. What is the resistance-power of an electric iron with 220V and 1100 watt?
11 Ω
33 Ω
22 Ω
44 Ω
26. 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.
27. Which one is a semiconductor material?
Phosphorous
Silicon
Rubber
Aluminium
28. Resistance of a conductor of diameter and length L is R ohm. It the diameter of the conductor is halved and its length is doubled the resistance will be-.
2R ohm
4R ohm
8R ohm
3R ohm
29. 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.
30. What type of material is Silicon (Si)?
Conductor
Semiconductor
Insulator
Good conductor
31. 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
32. The resistivity depends upon-
area
material
length
All of these
33. What voltage drop will be there across a 1kW flood light whose resistance when hot is 40 Ω ?
100V
50V
150V
200V
34. Unit of electrical energy is:
Newton-meter
Watt-sec
Watt
BTU
35. The unit of resistivity is-
Ohms
Ohm/Sqm
Ohm-m
None
36. 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.
37. Energy consumption of a 100-watt bulb for ten hours is
1000kWh
1 unit
100kWh
1kW
38. How many 60-watt bulbs will be safe for a home with main meter of 6 amp and 220 volts?
6
10
11
22
39. SI unit of electrical capacitance--
ohm
farad
henry
coulomb
40. Resistance depends on:
Cross section
Length
Material
All