Aqa A Level Physics Paper 1 Study Guide Graded A+

newton's second law {Ans: f=ma}Explain the difference between excitation and ionisation (2) {Ans: An electron receives a discrete amount of energy for BOTH (1) Excitation promotes an electron to a higher energy level Ionisation is when an electron receives enough energy to leave the atom}What is meant by ionisation energy? (2) {Ans: Minimum energy required to remove an electron from an atom (1) from the ground state (1)}What happens when annihilation occurs? (2) {Ans: particle and an anti-particle collide and cease to exist (1) Their mass is released as energy in the form of a pair of gamma photons (1)}Formation of a stationary wave {Ans: Two waves superpose (1) same wavelength and/or frequency (1) Travelling with equal and opposite velocity (direction of movement) (1)}Explain what is meant by forced vibrations (5) {Ans: forced vibrations = periodic force applied (1) frequency determined by as frequency of oscillator (1) phase difference is 180 degrees (pi rads) (1) frequency of driver > frequency of oscillator (1) amplitude small at high frequency and vice versa}define center of gravity {Ans: the point in a body (1) where the weight of an object appears to act (1)}define yield stress