Equations

Question 1

Work done

Answer 1

𝑊 = 𝐹 × 𝑑

Force F through distance d.

Question 2

Gravitational Potential Energy

Answer 2

GPE = 𝑚 × 𝑔 × ℎ

Mass m, height h.

Question 3

Kinetic Energy

Answer 3

KE = 1/2 𝑚𝑣²

Mass m, speed v.

Question 4

Efficiency

Answer 4

𝜂 = (useful energy output / total energy input) × 100%

Efficiency formula.

Question 5

Density

Answer 5

𝜌 = 𝑚 / 𝑉

Mass per unit volume.

Question 6

Refractive index

Answer 6

𝑛 = sin(𝑖) / sin(𝑟)

Angle of incidence i, refraction r.

Question 7

Critical angle

Answer 7

𝑛 = 1 / sin(𝑐)

Where c is the critical angle.

Question 8

Power

Answer 8

𝑃 = 𝐼 × 𝑉

Where I = current (A), V = voltage (V).

Question 9

Energy transferred

Answer 9

𝐸 = 𝐼 × 𝑉 × 𝑡

Or 𝐸 = 𝑄 × 𝑉.
Or 𝐸 = 𝑄 × 𝐼 × R .

Question 10

Ohm’s Law

Answer 10

𝑉 = 𝐼 × 𝑅

Where R = resistance (Ω).

Question 11

Charge

Answer 11

𝑄 = 𝐼 × 𝑡

Where Q = charge (C).

Question 12

Time Period for a wave

Answer 12

𝑇 = 1 / 𝑓

Time taken for one cycle.

Question 13

Pressure

Answer 13

𝑝 = 𝐹 / 𝐴

Force over area.

Question 14

Pressure in fluids

Answer 14

Δ𝑝 = ℎ × 𝜌 × 𝑔

Depth h, density ρ, gravity g.

Question 15

Boyle’s Law

Answer 15

𝑝₁𝑉₁ = 𝑝₂𝑉₂

At constant temperature.

Question 16

Specific heat energy

Answer 16

Δ𝑄 = 𝑚 × 𝑐 × Δ𝑇

Specific heat energy formula. m=mass c=specific heat capacity T=change in temp Q= change in thermal energy

Question 17

p/T = constant

Answer 17

𝑝₁/T₁ = 𝑝₂/T₂

at constant volume

Question 18

Power

Answer 18

𝑊𝒹/𝑡