Q: Which of the following is the correct formula for calculating the efficiency of a device?

$$\text{efficiency} = \frac{\text{useful energy output}}{\text{total energy output}} \times 100\%$$

Question 1

Which of the following statements best describes why the Pearson Edexcel International GCSE in Science (Double Award) is considered 'demanding' according to the World Class Qualifications framework?

Accepted Answer

The content and assessment are meaningful and meet the needs of end-users.

Question 2

Which of the following is a key feature of the 'inclusive' principle in the World Class Qualifications framework?

Accepted Answer

The qualification is accessible to all its target group of students.

Question 3

According to the Pearson Edexcel International GCSE in Science (Double Award) specification, which of the following is NOT a characteristic shared by all living organisms?

Accepted Answer

They can photosynthesize.

Question 4

Which of the following best describes the function of mitochondria in a cell?

Accepted Answer

They are the site of aerobic respiration and energy production.

Question 5

A student investigates the effect of temperature on enzyme activity. Which variable should be kept constant to ensure a fair test?

Accepted Answer

The type of enzyme used.

Question 6

Which equation correctly represents the relationship between force, mass, and acceleration?

Accepted Answer

$$F = m 	imes a$$

Question 7

A car travels 150 meters in 10 seconds. What is its average speed?

Accepted Answer

$$15\ 	ext{m/s}$$

Question 8

Which of the following best explains why substances with simple molecular structures have low melting and boiling points?

Accepted Answer

They have weak intermolecular forces.

Question 9

Which of the following is a correct statement about the transfer of energy in a food chain?

Accepted Answer

About 10% of energy is transferred from one trophic level to the next.

Question 10

Which of the following equations correctly represents the calculation of density?

Accepted Answer

$$\rho = \frac{m}{V}$$

Question 11

A student is asked to identify the gas produced when hydrochloric acid reacts with magnesium. Which test should they use?

Accepted Answer

Hold a burning splint near the gas; a 'pop' sound is heard.

Question 12

Which of the following best describes the role of control rods in a nuclear reactor?

Accepted Answer

They absorb neutrons to control the rate of fission.

Question 13

Which of the following is a property of sound waves?

Accepted Answer

They can be reflected and refracted.

Question 14

Which of the following is the correct formula for calculating the efficiency of a device?

Accepted Answer

$$	ext{efficiency} = \frac{	ext{useful energy output}}{	ext{total energy output}} 	imes 100\%$$

Question 15

Which of the following best describes why noble gases (Group 0) do not readily react?

Accepted Answer

They have a full outer shell of electrons.

Question 16

A student observes that a metal rusts more quickly in the presence of salt water than in pure water. Which scientific principle does this observation best illustrate?

Accepted Answer

The effect of impurities on the rate of corrosion.

Question 17

Which of the following is a correct statement about the Kelvin scale of temperature?

Accepted Answer

0 K is the lowest possible temperature, known as absolute zero.

Question 18

Which of the following best describes the difference between nuclear fusion and nuclear fission?

Accepted Answer

Fission splits large nuclei into smaller ones, while fusion joins small nuclei to form larger ones.

Question 19

Which of the following is a correct use of a light-dependent resistor (LDR) in a circuit?

Accepted Answer

To decrease resistance as light intensity increases.

Question 20

Which of the following best explains why only a small percentage of energy from sunlight is stored as chemical energy by plants?

Accepted Answer

Most sunlight is reflected or absorbed as heat.

Pearson Edexcel International GCSE in Science (Double Award): Physics Study Guide

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