IB Physics HL E 2 Quantum Physics Questions

apply stopping potential / OWTTE;

Marking guidance:

maximum kinetic energy =e V;

power supply negative connected to detector;
ammeter and voltmeter correctly connected;
Allow voltmeter connected directly across power supply.

Planck constant = gradient;

work function =(-) intercept on maximum kinetic energy (allow ' y ') axis;

$\quad \lambda_{0}=\frac{c}{\text { frequency intercept }}$ or $\frac{h c}{\text { max ke intercept }}$;

(value of intercept on f-axis $=) 9.3 \times 10^{14} \mathrm{~Hz}$;
Allow answers in the range of 9.0 to 9.5, but with correct power of ten.

attempted use of gradient $\left(\frac{h}{e}\right)$ to evaluate h;
eg $\frac{2.4}{6 \times 10^{14}}=4 \times 10^{-15} \mathrm{eVs}$; (allow answers in the range of 3.9 to $4.2 \times 10^{-15}$ ) $6.4 \times 10^{-34} \mathrm{Js}$; (allow ECF, eg answers in the range of 6.2 to $6.7 \times 10^{-34}$ )

Marking guidance:

Do not allow a bald answer of $6.6 \times 10^{-34}$ as value is known.
or
use of y-intercept $=\frac{-h f_{0}}{e}$;
$h=\frac{3.77 \times 1.6 \times 10^{-19}}{0.93 \times 10^{15}} ;($ allow intercept between -3.6 and -3.8 eV)
$6.4 \times 10^{-34} \mathrm{Js}$; (allow ECF, eg answers in the range of 6.0 to $6.8 \times 10^{-34}$ )
Do not allow a bald answer of $6.6 \times 10^{-34}$ as value is known.

$E=6.62 \times 10^{-34} \times 9.3 \times 10^{14}\left(=6.2 \times 10^{-19} \mathrm{~J}\right)$;
an answer in the range of 3.4 to 4.0 eV ;
(allow ECF from (e)(i) and (e)(ii))
or
identifies y intercept as work function;
an answer in the range of 3.6 to 3.8 eV ;