Conclusion and Discussion — practice questions

A student obtains an experimental value of $g = 9.6 \pm 0.5$ m s⁻².

State whether this is consistent with the accepted value of $9.81$ m s⁻², and justify your answer.

A student's linearised graph gives a gradient of $0.041 \pm 0.003$ and the theory predicts $0.045$.

Make a quantitative comparison of the experimental result with the theory, including consideration of uncertainties.

Two students test the same theory. Student A obtains a value within $1\%$ of the accepted value with a quoted uncertainty of $\pm 15\%$. Student B obtains a value $6\%$ from the accepted value with a quoted uncertainty of $\pm 2\%$.

Discuss which investigation provides better evidence about the theory.

State one assumption made by the theory $T = 2\pi\sqrt{L/g}$ that may not hold in a school laboratory.

In an investigation of how the resistance of a wire depends on its length, explain how the heating of the wire by the current could have affected the results, including the direction of the effect.

A student investigating how the period of a pendulum depends on length finds that their points at the shortest lengths sit consistently above the line of best fit on a graph of $T^2$ against $L$.

Discuss this outcome: give a cause, explain how it produces this specific pattern, and evaluate its effect on the validity of the conclusion.