Conductance : mho :: ____________?
Conductance : mho :: ____________?
A. resistance : ohm
B. capacitance : henry
C. inductance : farad
D. lumen : steradian
Conductance : mho :: ____________?
A. resistance : ohm
B. capacitance : henry
C. inductance : farad
D. lumen : steradian
If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes______________?
A. 0.4 ohm
B. 0.6 ohm
C. 0.8 ohm
D. 1.0 ohm
Which of the following quantities consists of SI unit as WATT ?
A. Force
B. Charge
C. Current
D. Power
The SI 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 to joules per second.
Assume 3 numbers of pure resistive loads each of value R.
When these loads are connected in delta the power in each resistor is V^2/R and the total power is 3×V^2/R.
When these loads are connected in star the voltage applied across each = V/(sqrt of 3). Power in each load becomes = V^2/(3×R) . and the total load is =(3×V^2)/(3×R)=V^2/R. You can see this is 3 times less than the total power when the loads are connected in delta.
One important point is that the loads should withstand higher voltage (line voltage) and higher current when connected in delta than when they are connected in star
so power in delta is 3 time power correct answer is 3P
Which of the following material has nearly zero temperature co-efficient of resistance_________?
A. Manganin
B. Porcelain
C. Carbon
D. Copper
The resistance of a conductor varies inversely as___________?
A. length
B. area of cross-section
C. temperature
D. resistivity
are the materials having electrical conductivity much less than most of the metals but much greater than that of typical insulators______________?
A. Varistors
B. Thermistor
C. Semi-conductors
D. Variable resistors