#180.
Which refers to the extraction of electrons from a substance by sunlight on incident
electromagnetic radiation?
A
Electron microscopy
B
Photoemission
C
Photovoltaic effect
D
Photoelectric effect
Answer: Photoelectric effect
#181.
Which statement is TRUE?
A
Bigger size of wire has lower resistance.
B
Long wire has lesser resistance.
C
Short wire has higher resistance.
D
Bigger size of wire has higher resistance.
Answer: Bigger size of wire has lower resistance.
#182.
A small light bulb with a resistance of 100 ohms is connected across a 120-v line. What is the
current through the bulb?
A
0.12 A
B
1.2 A
C
0.012 A
D
12 A
Answer: 0.12 A
#183.
A 200-v lamp has a resistance of 400 ohms. The power rating in watts of lamp is ________
A
100 w
B
600 w
C
200 w
D
250 w
Answer: 100 w
#184.
If 18 resistances, each of a value of 36 ohms, are connected in parallel, then the total resistance
is ________.
A
36 ohms
B
2 ohms
C
648 ohms
D
54 ohms
Answer: 2 ohms
#185.
A toaster takes 10 A from a 120V line. The power used is:
A
1,200 w
B
130 w
C
12 w
D
120 w
Answer: 1,200 w
#186.
How many kilowatts is the water heater if it draws a current of 10 amperes and has a resistance
of 23 ohms?
A
2.3 Kw
B
230 Kw
C
2,300 Kw
D
23 Kw
Answer: 2.3 Kw
#187.
The resistance of an electrical wire is inversely proportional to its ________.
A
cross sectional area
B
temperature
C
length
D
material
Answer: cross sectional area
#188.
A fluorescent lamp unit connected to a 110v AC line takes 1.2A and requires 110w power. What
is its power factor?
A
0.833
B
0.9
C
0.866
D
0.8
Answer: 0.833
#189.
An electric heater uses 20kw-in 8 hours. If the voltage across the heater is 240 volts. What is
the heater resistance?
A
23.04 ohms
B
83.3 ohms
C
2.5 ohms
D
2.30 ohms
Answer: 23.04 ohms
#190.
The resistance of a 230v incandescent lamp is 300 ohms. What current is required to operate
the lamp?
A
0.77 A
B
1.30 A
C
7.74 A
D
0.85 A
Answer: 0.77 A
#191.
A group of lamps operates a current of 12 A and a voltage of 120v. What is the total power of
the lamps?
A
1.44 kw
B
1.20 kw
C
14.4 kw
D
1.34 kw
Answer: 1.44 kw
#192.
What is the maximum load capacity of a 15A circuit breaker protecting a branch circuit that
supplies a continuous load?
A
12 A
B
10 A
C
15 A
D
14 A
Answer: 12 A
#193.
What is the horsepower rating of an electric water pump if it has a power rating of 1.75 Kw?
A
2.3 Hp
B
2 Hp
C
2.5 Hp
D
23 Hp
Answer: 2.3 Hp
#194.
How many kilowatts does a certain appliance consume for 5 hours of useif it has a power rating
of 1.5 Hp?
A
7.5 Kw
B
75 Kw
C
5.6 Kw
D
56 Kw
Answer: 5.6 Kw
#195.
A cell supplies a load current of 0.5A for a period of 20 hours until its terminal voltage falls to an
unacceptable level. How long can it be expected to supply a current of 100mA?
A
50 hours
B
60 hours
C
70 hours
D
100 hours
Answer: 100 hours
#196.
A battery is rated 200Ah. If it is used to supply a constant current of 8Ah. How long can the
battery last until it becomes unusable?
A
20 hours
B
15 hours
C
2.5 hours
D
2.5 hours
Answer: 2.5 hours
#197.
The resistance of 500 meters of a certain wire is 125 ohms. What length of the same wire will
have a resistance of 60 ohms?
A
240 meters
B
225 meters
C
24 meters
D
235 meters
Answer: 240 meters
#198.
If three equal resistances are connected in parallel,the equivalent resistance of the circuit will be
________ the value of one resistor.
A
one-third
B
the same
C
half
D
three time
Answer: one-third
#199.
Find the cost of using a 100W, 220V lamp for 20 hours at P3.00 per kW-hr?