A parallel plate capacitor of capacitance 86 µF is connected to a 6.00 kV power supply.
100 pF, 0.1 µF, 100 cF, 0.01 fF
Pressure at a certain depth in a fluid can be calculated using the value for the density of the fluid, the gravitational field constant g and the depth within the fluid.
(i) 20 000 kPa
(ii) 0.18 Gm
(iii) 1.15 μg
(iv) 82.6 pN
Pressure is measured in pascals.
Atmospheric pressure on Earth is 101 325 Pa. The Mariana trench at the bottom of the western Pacific Ocean has a pressure of around 110 MPa.
Pressure changes with depth, as well as force and area.
An electron microscope is used to analyse the arrangement of atoms and their nuclei on a new design for a special sheet of silver foil. The foil is a new material being added to various components in a military medical aircraft.
Estimate the orders of magnitude with an appropriate fundamental SI unit and correct prefix for the following quantities
|
Quantity |
Order of magnitude |
|
Mass of an aeroplane |
|
|
Radius of a proton |
|
|
Current through an LED |
|
|
Time between two heart beats |
|
The sheet of silver foil has a thickness of 0.992 µm. A silver atom has a radius of 172 pm.
Using the electron microscope, the cross–sectional area of the silver nuclei can be measured accurately in units of ‘barn’, with symbol b.
1 barn = 100 fm2
Einstein’s famous equation Energy (J) = Mass (kg) × (Speed of light (m s–1))2 demonstrates that energy and matter are interchangeable.
Atomic mass unit, 1 u = 931.5 MeV
1 eV = 1.60 × 10–19 J
X–ray pulsars are detected by X–ray telescopes on a satellite in low Earth orbit 2000 km above the surface of the Earth.
X–rays from a pulsar travel at the speed of light and are detected on Earth with a wavelength of 8.0 nm.
X–rays from the nearest pulsar PSR J0109–1431 take 8.82 Gs to travel to Earth.
A student conducts an experiment to study the variation of resistance R of a negative temperature coefficient (NCT) thermistor with temperature T. The data from the experiment is shown plotted on the graph.
The electric current through the thermistor for T = 283 K is 0.0078 mA.
Calculate the ratio 
when T = 291 K. Write your answer in fundamental SI units to an appropriate number of significant figures.
