**Basic Electrical Special MCQ Part One**

**1.The atomic number of an element is determined by**

- The number of neutrons.
- The number of protons.
- The number of neutrons plus the number of protons.
- The number of electrons.

**Answer-2**

**2.The atomic weight of an element is approximately determined by**

- The number of neutrons.
- The number of protons.
- The number of neutrons plus the number of protons.
- The number of electrons.

**Answer-3**

**3.Suppose there is an atom of oxygen, containing eight protons and eight neutrons in the nucleus, and two neutrons are added to the nucleus. The resulting atomic weight is about**

- 8
- 10
- 16
- 18

**Answer-4**

**4.An ion**

- Is electrically neutral.
- Has positive electric charge.
- Has negative electric charge.
- Might have either a positive or negative charge.

**Answer-4**

**5.An isotope**

- Is electrically neutral.
- Has positive electric charge.
- Has negative electric charge.
- Might have either a positive or negative charge.

**Answer-4**

**6.A molecule**

- Might consist of just a single atom of an element.
- Must always contain two or more elements.
- Always has two or more atoms.
- Is always electrically charged.

**Answer-1**

**7.In a compound**

- There can be just a single atom of an element.
- There must always be two or more elements.
- The atoms are mixed in with each other but not joined.
- There is always a shortage of electrons.

**Answer-2**

**8.An electrical insulator can be made a conductor**

- By heating.
- By cooling.
- By ionizing.
- By oxidizing.

**Answer-3**

**9.Of the following substances, the worst conductor is**

- Air.
- Copper.
- Iron.
- Salt water.

**Answer-1**

**10.Of the following substances, the best conductor is**

- Air.
- Copper.
- Iron.
- Salt water.

**Answer-2**

**11.Movement of holes in a semiconductor**

- Is like a flow of electrons in the same direction.
- Is possible only if the current is high enough.
- Results in a certain amount of electric current.
- Causes the material to stop conducting.

**Answer-3**

**12.A coulomb**

- Represents a current of one ampere.
- Flows through a 100-watt light bulb.
- Is one ampere per second.
- Is an extremely large number of charge carriers.

**Answer-4**

**13.If a material has low resistance**

- It is a good conductor.
- It is a poor conductor.
- The current flows mainly in the form of holes.
- Current can flow only in one direction.

**Answer-1**

**14.A stroke of lightning**

- Is caused by a movement of holes in an insulator.
- Has a very low current.
- Is a discharge of static electricity.
- Builds up between clouds.

**Answer-3**

**15.The volt is the standard unit of**

- Current.
- Charge.
- Electromotive force.
- Resistance.

**Answer-3**

**16.If an EMF of one volt is placed across a resistance of two ohms, then the current is**

- Half an ampere.
- One ampere.
- Two amperes.
- One ohm.

**Answer-1**

**17.A backwards-working electric motor is best described as**

- An inefficient, energy-wasting device.
- A motor with the voltage connected the wrong way.
- An electric generator.
- A magnetic-field generator.

**Answer-3**

**18.In some batteries, chemical energy can be replenished by**

- Connecting it to a light bulb.
- Charging it.
- Discharging it.
- No means known; when a battery is dead, you have to throw it away.

**Answer-2**

**19.A changing magnetic field**

- Produces an electric current in an insulator.
- Magnetizes the earth.
- Produces a fluctuating electric field.
- Results from a steady electric current.

**Answer-3**

**20.Light is converted into electricity**

- In a dry cell.
- In a wet cell.
- In an incandescent bulb.
- In a photovoltaic cell.

**Answer-4**