definitions

Question 1

Precision

Answer 1

• determined of the range in the values

Question 2

Accuracy

Answer 2

• determined by the closeness of the values to the true value

Question 3

High Precision

Answer 3

• measurements have a small range

Question 4

Low Precision

Answer 4

• measurements have large range

Question 5

Low accuracy

Answer 5

• the average of the measurements are not close to the

true value

Question 6

Systematic Error

Answer 6

• constant error in all readings
• cannot be eliminated by averaging
• eg: zero error of measuring apparatus

Question 7

Randon Error

Answer 7

• readings scatter equally about the true value
• errors can be eliminated by averaging
• eg: readings taken from different angles

Question 8

Mass of a body

Answer 8

• mass is the quantity of matter in a body

Question 9

weight

Answer 9

The force due to the gravitational field

Question 10

Displacement

Answer 10

Distance from a fixed point in a specific direction

Question 11

Linear momentum

Answer 11

mass x velocity

Question 12

Torque of a couple

Answer 12

Product of force and perpendicular distance between 2 forces

Question 13

Principle of moments

Answer 13

for a body in rotational equilibrium, sum of clockwise moment about a point is equal to sum of anti-clockwise moment about the same point

Question 14

Pressure

Answer 14

Force acting perpendicularly to unit of surface area

Question 15

Elastic limit

Answer 15

Elastic limit is a point beyond which the spring does not return to its original length when the load is removed

Question 16

Ultimate Tensile Stress

Answer 16

The maximum value of the ratio force to the original cross-sectional area where the wire is able to support

Question 17

Elastic Deformation

Answer 17

Change of shape or dimension and returns to original shape or size when the force applied is removed

Question 18

Plastic Deformation

Answer 18

When the load is removed, the body does not return to original shape/length

Question 19

Internal Energy

Answer 19

Sum of random kinetic energy and potential energy of the atom

Question 20

Potential Energy

Answer 20

Stored energy available to do work

Question 21

Elastic Potential Energy / Strain Energy

Answer 21

Energy stored in body due to deformation

Question 22

Interference

Answer 22

When 2 or more waves meet at a point, the resultant displacement is equal to the vector sum of displacement of individual waves

Question 23

Superposition

Answer 23

Constant phase difference between each of the waves

Question 24

Progressive wave

Answer 24

Transfer of propagation of energy as a result of vibration

Question 25

Polarisation

Answer 25

Vibration of particle in one normal to the direction of propagation of wave

Question 26

Speed of progressive wave

Answer 26

Speed at which energy is transferred

Question 27

Field line in an electric field

Answer 27

Path in which a free positive charge will move

Question 28

Electric Field

Answer 28

Region where a charge experiences a force

Question 29

Electric Field Strength

Answer 29

Force per unit positive small test charge

Question 30

Electric Potential Energy

Answer 30

Energy converted from electrical energy to other forms of energy per unit charge

Question 31

Electric current

Answer 31

rate of flow of charged particles

Question 32

Charge

Answer 32

current x time

Question 33

Random nature

Answer 33

The curve is not smooth

Question 34

Spontaneous nature

Answer 34

The curve has the same shape with constant half life

Question 35

Radioactive decay of a nucleus

Answer 35

Spontaneous and random decay of unstable nucleus become more stable by emitting alpha/beta particles /gamma rays

Question 36

Spontaneous radioactive decay

Answer 36

Decay is not affected by the environmental changes such as temperature, pressure

Question 37

Random decay

Answer 37

Constant probability of decay per unit time of nucleus and cannot predict which particular nucleus will deacy next

Question 38

Random

Answer 38

the observations of the count rate shows variations

Question 39

Alpha particle

Answer 39

Helium nucleus with 2 protons and 2 neutrons

Question 40

Beta particle

Answer 40

High-speed electron

Question 41

Gamma Radiation

Answer 41

Electromagnetic photon

Question 42

what do the symbols represent in I=nave

Answer 42

A - cross-sectional area N - number density of free electrons v - drift velocity of free electrons