Physics Ch: 1

What is a standard in physics measurements?

An absolute primary reference.

What is calibration?

The process of configuring an instrument to match with standards.

What is precision?

When several readings are close together (consistent).

What is accuracy?

How close a measurement is compared to the true value.

What is zero error?

An error when an instrument shows a non-zero reading at rest (can be positive/negative). Must be corrected.

What is least count?

The minimum measurable value or the value of one subdivision of a calibrated instrument.

What is parallax error?

Error when the level of eyesight is not perpendicular to the scale readings.

Define mass.

Property of an object to resist any change in motion; causes gravitational attraction.

Define density.

Ratio of mass to volume of a substance (rho = m/V).

How to measure the length of a pendulum (method 1)?

Add the length of the string to the radius of the bob.

How to measure the length of a pendulum (method 2)?

Use a set square aligned with the bob for horizontal reference.

How to measure the length of a circular object?

Wrap string around it, measure string length with ruler, repeat for diameters and average.

How to measure thickness of a sheet of paper?

Measure height of several sheets and divide by number of sheets (averaging).

Formula for volume of a sphere?

V = (4/3) * pi * r^3

Formula for volume of a cube/cuboid?

V = l * b * h

Formula for volume of a cone?

V = (1/3) * pi * r^2 * h

How to measure volume of irregular objects?

Use water displacement method in a measuring cylinder; final - initial volume = object volume.

What is the relation between volume displaced and irregular object?

Volume of displaced liquid = volume of irregular object.

How to measure density of an unknown liquid?

Find mass of empty cylinder, add liquid, subtract to get liquid mass, then use rho = m/V.

Difference between analogue clocks and digital timers?

Analogue uses hands (less precise, more errors). Digital displays readings, precise up to 0.01s.

Define time period of a pendulum.

Time taken for one oscillation.

Define frequency.

Reciprocal of time period (number of oscillations per unit time).

Why measure multiple oscillations of pendulum?

Reduces percentage uncertainty due to reaction time errors.