A. 230 V
B. 210 V
C. 208 V
D. 205 V
Ans: C. 208 V
Explanation:
In north America , three phase supply have 208 V between phases and 120V between phases and neutral.
In India , three phase supply have 440 V between phases and 220V between phase and Neutral.
More MCQ
1. A four wire system allows you to have ........
A. Phase to Phase Voltage only
B. Phase to Neutral Voltage only
C. Both Phase to Phase voltage & Phase to Neutral voltage
D. None of above
Ans: C. Both phase to phase Voltage & Phase to Neutral Voltage
Explanation :
3 phase & 4 wire system having provide three phases and neutral wire. in this system phase to phase voltage is 440V and phase to neutral voltage is 220 V.
2. If the three color bands of resister are red, orange and yellow. then the value of resistance is
A. 240 mega Ohm
B. 230 mega ohm
C. 22 mega ohm
D. 21 mega ohm
Ans: B. 230 mega ohm
Explanation :
Here color bands for resister are Red, orange and yellow
first we know about the color code of resister
Color code for resister value
Black -- 0
Brown -- 1
Red -- 2
Orange --3
Yellow --4
Green --5
Blue --6
Violet --7
Grey --8
White --9
Color code for tolerance
Gold-- 5%
Silver -- 10 %
No Color -- 20 %
Take Digit for first and second color and take number of zero for third digit
here given color are red --2 orange --3 & yellow --4 nos of zero
Value of resistance is 230000 Ohm called it 230 mega ohm.
3. Which have negative temperature of coefficient resistance ?
A. Copper
B. Aluminum
C. Brass
D. Insulators
Ans : D. Insulators
Explanation :
Insulator have negative temperature of coefficient resistance.
4. Electrical Heater is rated as 3000W ,230V then the value of heater coil is
A. 17.7 ohm.
B. 17.6 ohm
C. 17.2 Ohm
D. 17.3 ohm
Ans: 17.6 ohm
Explanation :
Here here wattage of heater are given that 3000W and voltage is Given that 230V
formula Power P = v2/ R
Here P = 3000 W
V = 230 V
R = ?
so Formula become
R = v2 / P
R = 230 * 230 / 3000
R = 52900 / 3000
R = 17.6 ohm