Practice Questions

Name : ______

Practice Questions

The heating element of an electric stove has a resistance of 50. It is connected to a power source of 220V and turned on for 2.0minutes.

What is the current which flows through this heating element?

A) / 4.4 A B) 8.8 A C) 9.1 A D) 27.3 A

A voltage of 100V, is applied to the ends of a metal conductor for 20 seconds. The current passing through this conductor is 5.0A.

What is the resistance of the metal conductor?

A) / 400  B) 100  C) 20  D) 1 

A magnet creates what is known as a magnetic field. A compass can be used to show the magnetic field.

Which of the following statements are true?

1. / If a bar magnet is broken in two, each piece will only have one magnetic pole.
2. / Like poles repel each other.
3. / The needle of a compass is a small magnet.
4. / Aluminum can be easily magnetized.
A) / 1 and 2 B) 1 and 4 C) 2 and 3 D) 3 and 4

Aramis uses an electric mixer to whip some cream in a mixing bowl. The power of the motor is 10 W. After using the mixer for 5 min, he calculates that the cream has absorbed 1200J of thermal and mechanical energy.

What amount of electrical energy used by the motor was not absorbed by the cream?

A) / 50 J B) 1150 J C) 1800 J D) 3 000 J

A metal conductor consumes 1200J of energy in 1.0 minute when it is connected to a voltage of 10.0 V. How much energy would it consume if the voltage were 20.0 V during the period of 1.0 minute?

A) / 300 J B) 600 J C) 2 400 J D) 4 800 J

Combustion is a chemical reaction that occurs under certain conditions. The fire triangle below illustrates conditions required for combustion to occur.

A friend shows you the three conclusions she arrived at after doing her research on forest fires:

a) If the wind increases, the forest fire will also increase.

b)Forest fires are more common in summer, when it is hot and dry, than in autumn, when it is cold and wet.

c) Forest fires are more likely to occur in mature forests than in young forests.

Justify each of the conclusions by using the fire triangle.

A straight magnet always produces an external magnetic field.

In which of the following diagrams is this magnetic field correctly represented?

A) / / C) /
B) / / D) /

Several factors can influence the electrical conductivity of a wire.

Which of the following diagrams shows the wire with the best electrical conductivity?

Note the following substances :

1. Rubber4. Copper

2. Plastic5. Steel

3. Aluminum

Which of these substances are insulators?

A) / 1 and 2 B) 1 and 3 C) 2, 4 and 5 D) 3, 4 and 5

In order to extend the life of a race car, the students attach a bumper to it. The table below lists the mechanical properties of four different materials.

MATERIALS
MECHANICAL PROPERTIES / Malleable / TXA / TXB / TXC / TXD
Ductile / No / Yes / Yes / No
Flexible / Somewhat / Yes / Yes / Somewhat
Fragile / No / No / Yes / Somewhat
No / Somewhat / No / Somewhat

Choose the material that should be used in order to make the bumper as resistant as possible to impact. Justify your answer.

The following observations were made when certain pairs of objects were brought close together.

STEP / TEST / OBSERVATION
1 / Brought an iron nail near a zinc rod. / No reaction
2 / Brought an iron nail near a steel rod. / Attraction
3 / Brought a zinc rod near a steel rod. / No reaction
4 / Brought an iron nail near another iron nail. / No reaction

Given these observations, which of the following statements is TRUE?

A) / The iron nail is non-magnetic and the zinc rod is ferromagnetic.
B) / The steel rod is ferromagnetic and the zinc rod is ferromagnetic.
C) / The steel rod is magnetic and the zinc rod is non-magnetic.
D) / The iron nail is magnetic and the zinc rod is magnetic.

Each of the following diagrams shows a $0.25 coin placed in front of a solenoid.

Which of these solenoids attracts the coin the most?

An electrical circuit consists of a power source, two switches (S1 and S2) and two light bulbs (L1 and L2).The following table shows what happens to both light bulbs:

Switch / Light Bulb
S1 / S2 / L1 / L2
open / open / out / out
closed / open / bright / out

Which of the following circuit diagrams illustrates the results shown in the table above?

A) / / C) /
B) / / D) /

Four electric circuit diagrams are given below.

Only one of these diagrams correctly represents:

-a voltmeter connected across the terminals of resistor R1

-an ammeter measuring the current flowing through resistor R2

Which diagram is it?

A) / Diagram 1 B) Diagram 2 / C) / Diagram 3 D) Diagram 4

An electrical appliance has a defective resistor with a resistance of 5. You are asked to replace this resistor.

The following table provides information about four resistors you have been given.

Table I -Potential Difference across the Terminals ofthe Four Resistors

and the Current Flowing Through Them

Resistor / Potential Difference
(V) / Current
(A)
1 / 2 / 0.4
2 / 6 / 0.5
3 / 15 / 2.5
4 / 20 / 2.0

Which one of these resistors should you use to replace the defective resistor?

A) Resistor 1 B) Resistor 2 C) Resistor 3D) Resistor 4

The following diagram shows a bar magnet and four compasses. Which compass shows the needle pointing in the correct direction?

The following diagram shows a magnet, an electromagnet and a small car containing iron.

What happens when an electric current flows through the electromagnet?

A)The magnet and the car are attracted.

B)The magnet and the car are repelled.

C)The magnet is attracted, and the car is repelled.

D)The magnet is repelled, and the car is attracted.

Alligator clips are used to connect the components of an electric circuit.

Which substance can be used to make the jaws of these alligator clips?

A) / Aluminum B) Rubber C) Plastic D) porcelain

A battery-operated toy police car has 3 types oflights that can come on in different ways.

The car has only one electrical circuit that controls the lights.

The headlights and the taillights come on when you start the car.

Ifnecessary, the flashing light can come on at the same time as the headlights and the taillights.

This toy police car is illustratedin the diagram below.

Which of the following diagrams represents the electrical circuit that can control the lights in this toy police car?

Which of the following balanced equations represents an oxidation reaction?

A)C3H8+5O23CO2+4H2O

B)6CO2+6H2O+energyC6H12O6+6O2

C)2NaOH+H2SO4Na2SO4+2H2O

D)Pb(NO3)2 (aq)+2KI(aq)PbI2 (s)+2KNO3(aq)

The electrical circuit ofa magnetic alarm system is illustrated in the diagram below.

Which of the following shows the correct match between the five numbered components in this circuit diagram and their corresponding electrical functions?

A)1- control 2- conduction 3- transformation 4- power supply 5- protection

B)1- control 2- conduction 3- power supply 4- transformation 5- protection

C)1- power supply 2- protection 3- transformation 4- control 5-conduction

D)1- power supply 2- conduction 3- protection 4- transformation 5- control