5.2.4a Half-life

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Question 46

The radioactive isotope sodium-24 ( $1124Na^{24}_{11}\text{Na}$ ) decays by $β\beta$ -particle emission to an isotope of magnesium (Mg).

Complete the nuclide equation that represents this decay.

^{24}_{11}\text{Na} \rightarrow {}^{\dots\dots}_{\dots\dots}\text{Mg} + {}^{\dots\dots}_{\dots\dots}\beta

[2]

A radiation detector is placed on a bench in a laboratory where there are no artificial sources of radiation. The detector is switched on. In six one-minute periods, the detector displays these readings:

\quad 15, \quad 17, \quad 16, \quad 14, \quad 16

Explain why, in the absence of any artificial source, there are readings on the detector. Suggest one origin of this effect.

[2]

Explain why the readings obtained are not all the same.

[1]

The half-life of sodium-24 is 15 hours. A sample of sodium-24 is brought close to the detector and in one minute, the reading displayed is 592. The equipment is left in the same place for exactly 45 hours. Predict the reading in a one-minute period at the end of this time.

[5]

The radioactive isotope sodium-24 ( $1124Na^{24}_{11}\text{Na}$ ) decays by $β\beta$ -particle emission to an isotope of magnesium (Mg).

Complete the nuclide equation that represents this decay.

^{24}_{11}\text{Na} \rightarrow {}^{\dots\dots}_{\dots\dots}\text{Mg} + {}^{\dots\dots}_{\dots\dots}\beta

[2]

\quad 15, \quad 17, \quad 16, \quad 14, \quad 16

Explain why, in the absence of any artificial source, there are readings on the detector. Suggest one origin of this effect.

Explain why the readings obtained are not all the same.

[1]

[5]

5.2.4a Half-life

Question 46

Markscheme

5.2.4a Half-life

Question 46

Markscheme

5.2.4a Half-life

Question 46

5.2.4a Half-life Questions

5.2.4a Half-life

Question 46

5.2.4a Half-life Questions