Williams Tech.Smartlearners

How can you calculate the total resistance of a combination of resistors in series? The total resistance equals the sum of the individual resistances. R = R₁ + R₂...+ Rₙ How can you calculate the total resistance of a parallel combination of resistors? The total resistance equals the inverse of the sum of the inverses of the individual resistances. 1/R = 1/R₁ + 1/R₂...+ 1/Rₙ What device can be used to check the resistance of a component? An Ohmmeter or multimeter can be used t...

What is an uncertainty? An uncertainty in a measurement is anything that may cause the value to differ from the true value. What is the resolution of a measuring instrument? The resolution of an instrument is the smallest increment that produces a noticeable change in the value. How do you combine uncertainties when adding values? Add the absolute uncertainties. How do you combine uncertainties when subtracting values? Add the absolute uncertainties. How do you combine uncertainties wh...

Absolute Uncertainty The interval that a value is said to lie within, with a given level of confidence. Accuracy A measure of how close a measurement is to the true value. Analogue Apparatus Measuring apparatus such as rulers, beakers and thermometers that rely on the experimenter reading off a scale to determine the measurement. Anomalies Data points that don’t fit the pattern of the data. You should determine why an anomalous result has occurred before removing it. Repeat readings...

1. Define the term ‘progressive wave’. A wave that transfers energy from one place to another with a wave front which travels through the material (in contrast to stationary waves which don’t appear to move). 2. What is a longitudinal wave? Waves which the particles oscillate in the same direction as energy propagation. 3. There are rarefactions (areas of low pressure) and compressions (areas of high pressure). 4. What is a transverse wave? Give examples. Waves where the particl...

How does the alpha-scattering experiment give evidence of a small, dense nucleus? A few alpha particles bounce back. This wouldn’t happen if the positive charge in the atom was distributed evenly throughout (as in the Plum Pudding Model), which suggests they must be hitting a dense positive charge. The fact it only happens to a very small number of alpha particles shows the nucleus must be small. What are the main constituents of an atom? ● Proton ● Neutron ● Electron How many ...

Absolute Temperature A temperature value relative to absolute zero. Absolute Zero The lowest possible temperature of a system, where no heat remains and the particles in the system have no kinetic energy. Avogadro Constant The number of particles that make up one mole of any gas. Boltzmann Constant A constant relating the average kinetic energy of the particles in a gas, to the gas’ temperature. Boyle’s Law The pressure of an ideal gas is inversely proportional to its volume when ...

Define Magnetic Field. A region of space in which moving charged particles are subject to a magnetic force. This force is caused by the interaction of two Magnetic Fields (there is a field around the moving charged particles which interacts with the existing Magnetic Field they are passing through). Define Magnetic Field Line. The path which a north pole would take when placed in a Magnetic Field. Field lines go from north to south. How can you map field lines around a magnet? You can p...

Why are X-rays used in medical imaging often referred to as ‘soft X-rays’? Because they have energies that are lower than gamma rays. How are X-rays produced? By rapidly accelerating or decelerating charged particles – their kinetic energy is transferred into highenergy photons How can you differentiate between X-rays and Gamma rays? X-rays and gamma rays have frequencies that overlap, so you cannot distinguish them by their wavelengths. Instead you have to use their method of prod...

Define Young’s Modulus. The Young’s Modulus of a material its ratio of tensile stress to tensile strain. It is a measure of a material’s stiffness. How is stress calculated? Stress = Force/Cross-Sectional Area How is strain calculated? Strain = Change in Length/Original Length What is the unit of stress? Pascals (Pa) or N⋅m⁻² What is the unit of strain? Strain doesn’t have a unit since it is a ratio of two lengths. What is the unit of Young’s Modulus? Pascals (Pa) or ...

What is meant by free-fall? An object is said to be falling in free-fall if the only force acting on it is gravity. This means that no resistive forces are acting (or in practice they are considered negligible). What is ‘g’? Gravitational Field Strength (in our case, on the surface of Earth). Why can the SUVAT equations be used in this experiment? The SUVAT equations can be used since the object will fall with uniform acceleration. This is because the force of gravity is constant a...