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WorksheetsĐề Mr Nghiêm
Total questions: 40
Worksheet time: 20mins
A 20 cell battery with each cell having an internal resistance of 0.1 ohms is
charged with 2 leads having a total resistance of 0.1 ohms. The battery is charged
with a current of 5 amps. What is the charging voltage ?
10.5V
9.5V
11.5V
Two 10V, 20 Ah batteries are connected in parallel and connected across a 10
ohm load. How long could they supply normal current before the voltage begins
to decay?.
40 hours
30 hours
50 hours
Two batteries 12V and 40 Ah each, are in series. What is the total capacity?.
24V 40Ah
12V 80Ah
24V 80Ah
If a battery has got low internal resistance, what is relation between no load voltage and on load voltage.
No load voltage will be greater than on load voltage
On load voltage will be greater than no load voltage
No load voltage will be the same as on load voltage
How do conventional current flow inside a battery
Anode to cathode
Cathode to anode
Two 12V 40 amp hour batteries connected in parallel, what DC source will be produced.
12V 80amp
24V 40amp
24V 80amp
A 24-volt source is required to furnish 48 watts to a parallel circuit consisting of four resistors of equal value. What is the voltage drop across each resistor?.
24V
12V
36V
In a thermocouple, where is voltage measured?
At the cold junction
At the hot junction
Ceramic insulators
The capacity of a battery is measured in
Ampere-hours
Voltage-hours
Ohm
Which component generate a voltage when it is exposed to light?.
Photodiode
Laser diode
Zener diode
Can a primary cell be recharged
Can not recharged
Can be recharged
What is the internal resistance of a battery?
The resistance present inside the battery while connected to a load
The resistance present inside the battery while disconnected to a load
The voltage present inside the battery while connected to a load
The resistance of a material is
The reciprocal of its conductance
The conduction of its conductance
The absorbation of its conductance
When will the electron flow through a conductor be decreased
The cross-sectional area decreased and the length increased
The cross-sectional area increased and the length decreased
The cross-sectional area increased and the length increased
Potentiometers are used as a
Variable resistor
Battery
Ammeter
If a number of resistors are connected in parallel, the total resistance is
Decrease
Increase
Not change
The resistance to electrical flow in a wire depends on
the diameter, length, material of wire and temperature
the diameter, material of wire
Only temperature
When resistors are in parallel the total current is equal to
The sum of current
The average of current
The multiple of current
Which of these will cause the resistance of a conductor to decrease?
Decrease the length or increase the cross-sectional area
Decrease the length or decrease the cross-sectional area
Increase the length or increase the cross-sectional area
In a parallel circuit containing resistors
The voltage is the same in all parts of the circuit
The current is the same in all parts of the circuit
The voltage is not the same in all parts of the circuit
Five different value resistors all have the same voltage dropped across them. How are the resistors connected?.
Parallel
Series
Don't know
What is properties of a potentiometer?
3 terminals
2 terminals
4 terminals
What happens to the resistance of a copper conductor when the temperature increases?.
It increases
It decreases
It does not change
The 5th coloured band on a resistor represents the
Tolerance
Multiplier
3rd digit
If the temperature of a pure metal is reduced to absolute zero, its resistance will be
Practically zero
Practically one
Practically ten
A 10 V battery supplies a resistive load of 10 ohms for 1 minute. What is the power supplied?
10W
100W
1W
Power in a DC circuit is found by
I^2*R
I*R^2
I^2/R
A solenoid of 10 turns per metre carries a current of 5A. If the current is reduced to 2.5A, how many turns would be required to maintain the same magnetic field?
20
15
25
Where is the earth's magnetic field greatest
Magnetic poles
Equator
Russia
What happen if the North pole of a magnet is brought nearer to the North pole of another magnet
They pushes each other away
They attract each other
Nothing happens
What is the unit of flux
Weber
Ohm
Ampe
How are lines of magnetic flux pass
North to South
South to North
West to East
Magnetic fields around two parallel conductors carrying current in the same directions will
Attract
Push away
Get burnt
A paramagnetic material has a relative permeability of
Greater than unity
Smaller than unity
Equal to unity
Through which material will magnetic lines of force pass the most readily?
Iron
Carbon
Steel
Which term is used to denote the strength of a magnetic field
Flux density
Flux color
Flux weight
Why is a soft iron core used in an electromagnet
It demagnetizes easily
It is difficult to demagnetize
It is durable
What happen if a bar magnet is cut in half
Two bar magnets are formed
There are 4 magnet bars
There are 8 magnet bars
The MMF of a coil fed with 2 amps and having 10 turns is
20 ampe turns
40 ampe turns
60 ampe turns
Magnetic flux saturation takes place when
The magnetised medium will accept no further lines of flux
The magnetised medium will attract a lots lines of flux.
