Equations

Question 1

You want to find the number of moles of X. You have Current, time and you know that 1 mole = 96,500 C. What equation(s) do you need?

Answer 1

Q = IT, n = Q/e

Question 2

A ball, 3kg, is rolling down a hill at 5ms-1 and stops at the bottom. What is the height of the hill.

Answer 2

mgh + 1/2 mv^2 = 0

Question 3

Two particles at distance X are now at distance 2X from each other, what is the force between them?

Answer 3

F = k(q1q2/r^2)

Question 4

Calculate the energy of a light beam with wavelength 500nm that travels at 4 * 10^-6 ms-1.

Answer 4

v = lambda*f, E = hf

Question 5

Calculate the change in pressure when a U-shaped tube filled with water rises by 2cm on the right side. (Density of water 1000kgm^3)

Answer 5

Delta P = pgh

Question 6

A microscope has magnification 20X. What is the height of an object that has a image height of 2cm?

Answer 6

M = i/o

Question 7

What is the distance travelled by a softball thrown at 2ms-1 in 10 seconds through the air?

Answer 7

S = ut + 1/2at^2

Question 8

What is the half life of a sample that began with 2000 ml of substance C and finished with 20 ml?

Answer 8

Final/Initial -> raise(1/2) to the n value that equates (1/2)^n to fraction of activity

Question 9

A beam of light travels from air to glass at a speed of 2 * 10^8 m/s. It hits the glass at a 50 degree angle. What is the angle of reflection?

Refractive Index of glass = 1.55

Answer 9

n = c/v, n2/n1 = sin(theta)1/ sin(theta)2

Question 10

100 grams of blood passes through a 4cm radius blood vessel in 10 seconds from 2 ms^-1 to 6ms-1. What is the pressure exerted on the vessel walls?

Answer 10

P = F/A

Question 11

A block is placed in a litre of water, it floats halfway above the water. What is it’s buoyancy force?

Answer 11

FB = V(displaced volume)pg