Q1. Which of the following is not a possible value for q?

Background

Topic: Quantization of Electric Charge

This question tests your understanding of how electric charge is quantized in units of the elementary charge, .

Key Terms and Formulas:

• Elementary charge, C

• Quantization of charge: , where is any integer (positive or negative)

Step-by-Step Guidance

1. For each option, divide the given charge value by to see if the result is an integer.

2. If the result is not an integer, that value is not possible for (since charge must be an integer multiple of ).

3. Check each option carefully and note which one does not yield an integer when divided by .

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Q3. What are some good electrical conductors?

Background

Topic: Properties of Electric Charge & Classification of Substances

This question is about identifying materials that allow electrons to move freely, making them good conductors of electricity.

Key Terms:

• Electrical conductor: A material that allows the flow of electric charge (usually electrons) easily.

• Examples: Metals are typically good conductors.

Step-by-Step Guidance

1. Recall which materials are commonly used in electrical wiring and circuits.

2. Think about why metals are used for wires and connections in everyday devices.

3. List at least two metals that are known for their high electrical conductivity.

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Q4. What are some good electrical insulators?

Background

Topic: Properties of Electric Charge & Classification of Substances

This question asks you to identify materials that do not allow electrons to move freely, making them good insulators.

Key Terms:

• Electrical insulator: A material that resists the flow of electric charge.

• Examples: Non-metals like rubber, glass, and plastic are common insulators.

Step-by-Step Guidance

1. Think about materials used to coat or cover electrical wires for safety.

2. Recall which substances are used to prevent electric shocks or short circuits.

3. List at least two materials that are known for their insulating properties.

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Q5. What are some semi-conducting materials?

Background

Topic: Properties of Electric Charge & Classification of Substances

This question is about materials that can act as conductors or insulators depending on conditions, such as the presence of impurities.

Key Terms:

• Semiconductor: A material with electrical conductivity between that of a conductor and an insulator.

• Examples: Silicon and germanium are classic semiconductors.

Step-by-Step Guidance

1. Recall which materials are used in electronic devices like diodes and transistors.

2. Think about the periodic table and which elements are commonly used in the semiconductor industry.

3. List at least two elements or compounds that are widely used as semiconductors.

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Q6. Sphere X has a net charge of 6.4 C. It is placed in contact with a neutral identical sphere Y and then removed. Sphere Y is then placed in contact with a neutral identical sphere Z and then removed. What are the final charges on spheres X, Y, and Z?

Background

Topic: Charging by Conduction

This question tests your understanding of how charge is redistributed when identical conductors are brought into contact and then separated.

Key Concepts and Formulas:

• When two identical conductors touch, the total charge is shared equally.

• Conservation of charge: The total charge before and after contact remains the same.

Step-by-Step Guidance

1. Calculate the charge on each sphere after X and Y touch and are separated.

2. Next, calculate the charge on Y and Z after they touch and are separated.

3. Remember to keep track of the charge on each sphere after each step.

4. Use the principle that identical spheres share charge equally when in contact.

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