Grade 11 Physics Midterm Review

Which of the following sources of electricity has the lowest environmental impact?

• Coal

• Nuclear

• Wind

• Natural Gas

Answer explanation

Wind energy has the lowest environmental impact as it produces no emissions during operation, unlike coal and natural gas, which release greenhouse gases, and nuclear, which has concerns about radioactive waste.

What is the primary disadvantage of using solar energy?

• High initial cost

• Non-renewable

• Produces greenhouse gases

• Limited availability

Answer explanation

The primary disadvantage of using solar energy is the high initial cost of installation and equipment, which can be a barrier for many individuals and businesses despite its long-term savings and environmental benefits.

Kirchhoff's Voltage Law states that:

• The total current entering a junction equals the total current leaving the junction.

• The voltage across a resistor is proportional to the current flowing through it.

• The product of current and resistance is constant.

Answer explanation

Kirchhoff's Voltage Law states that the total voltage around a closed loop equals zero. However, the correct choice here is actually Kirchhoff's Current Law, which states that the total current entering a junction equals the total current leaving it.

In a series circuit, the total resistance is:

• Less than the smallest resistor

• Equal to the smallest resistor

• The sum of all resistances

• The reciprocal of the sum of reciprocals of all resistances

Answer explanation

In a series circuit, the total resistance is calculated by adding the resistance values of all components. Therefore, the correct answer is 'The sum of all resistances', as it accurately describes how total resistance is determined.

Which of the following describes a parallel circuit?

• Only one path for current to flow

• Multiple paths for current to flow

• Current is the same through all components

• Voltage is the same across all components

Answer explanation

A parallel circuit has multiple paths for current to flow, allowing different components to operate independently. This distinguishes it from a series circuit, which has only one path.

What happens to the total resistance in a parallel circuit if one more resistor is added?

• It increases

• It decreases

• It remains the same

• It doubles

Answer explanation

In a parallel circuit, adding another resistor provides an additional path for current to flow. This reduces the total resistance, as the overall resistance is calculated using the reciprocal formula. Thus, the total resistance decreases.

According to Ampere's Law, the magnetic field around a current-carrying wire is:

• Directly proportional to the current and inversely proportional to the distance from the wire.

• Inversely proportional to the current and directly proportional to the distance from the wire.

• Directly proportional to the current and distance from the wire.

• Inversely proportional to the current and distance from the wire.

Answer explanation

According to Ampere's Law, the magnetic field (B) around a current-carrying wire is directly proportional to the current (I) and inversely proportional to the distance (r) from the wire, expressed as B ∝ I/r.

Which of the following statements is true about Oersted's Principle?

• A current-carrying wire generates an electric field.

• A current-carrying wire generates a magnetic field.

• A magnetic field generates a current in a nearby wire.

• An electric field generates a current in a nearby wire.

Answer explanation

Oersted's Principle states that a current-carrying wire generates a magnetic field around it. This is the correct choice, as the other statements incorrectly describe the relationships between electric and magnetic fields.

If a wire is placed in a magnetic field, the direction of the force on the wire can be determined using:

• Otiw's Law

• Faraday's Law

• Kirchhoff's Law

• Right-hand rule

Answer explanation

The direction of the force on a wire in a magnetic field is determined using the Right-hand rule. This rule helps visualize the relationship between the current, magnetic field, and the resulting force.

The accuracy of an experiment refers to:

• The closeness of a measurement to the true value.

• The repeatability of measurements.

• The degree of exactness of a measurement.

• The difference between the measured and true values.

Answer explanation

The accuracy of an experiment is defined as the closeness of a measurement to the true value. This means that a measurement is considered accurate if it is near the actual or accepted value.