C plates must be conductors plates must be conductors p1.94 (a) The shadow of the cross showed that the cathode rays travelled in straight lines. Without the cross there is no shadow. (b) The glass fluoresces because the energy carried by the electrons are absorbed by the glass molecules. The molecules of the glass become and excited and then loss energy by emitting photons of visible light. (c) The cathode rays are negatively charged electrons negative charged particles – moving in a magnetic field experience a force electron beam deflected causing a – distortion of the shadow of the cross. (d) Electrons are constituent of atoms, investigate properties of electrons, measure the ratio. qe/me (e) Need a high voltage source such as an induction coil ******************************************************************* p2.05 across the gap of the transmitter produced the induction coil emitted electromagnetic radiation which included radio waves and UV radiation. When a sheet of glass was placed between the transmitter and receiver, the spark in the receiver was weaker due to the absorption of the UV by the glass. Hertz noted the observation but did not follow it up. The UV absorbed by the metal receiver enabled electrons to be mitted more easily giving a bigger spark photoelectric effect. – p2.06 Planck energy of atomic oscillators is quantized = E h f Einstein particle model for light light consisted of photons energy of each photon hf – – An electron emitted immediately from the surface by the interaction with a photon Applied the Law of Conservation of Energy Energy of incident photon = Energy to release electron from surface + KE of ejected electron ½ ½ h f = m v2 + = m vmax2 + W is the min energy needed to remove an electron from the surface work function W –
C plates must be conductors plates must be conductors p1.94 (a) The shadow of the cross showed that the cathode rays travelled in straight lines. Without the cross there is no shadow. (b) The glass fluoresces because the energy carried by the electrons are absorbed by the glass molecules. The molecules of the glass become and excited and then loss energy by emitting photons of visible light. (c) The cathode rays are negatively charged electrons – negative charged particles moving in a magnetic field experience a force – electron beam deflected causing a distortion of the shadow of the cross. (d) Electrons are constituent of atoms, investigate properties of electrons, measure the qe/me ratio. (e) Need a high voltage source such as an induction coil ******************************************************************* p2.05 across the gap of the transmitter produced the induction coil emitted electromagnetic radiation which included radio waves and UV radiation. When a sheet of glass was placed between the transmitter and receiver, the spark in the receiver was weaker due to the absorption of the UV by the glass. Hertz noted the observation but did not follow it up. The UV absorbed by the metal receiver enabled electrons to be mitted more easily giving a bigger spark – photoelectric effect. p2.06 Planck energy of atomic oscillators is quantized E = h f Einstein particle model for light – light consisted of photons – energy of each photon hf An electron emitted immediately from the surface by the interaction with a photon Applied the Law of Conservation of Energy Energy of incident photon = Energy to release electron from surface + KE of ejected electron h f = ½ m v2 + = ½ m vmax2 + W W is the min energy needed to remove an electron from the surface – work function
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