Q2. A teacher used a Geiger-Muller tube and counter to measure the number of counts in 60 seconds for a radioactive rock. (a) The counter recorded 819 counts in 60 seconds. The background radiation count rate was 0.30 counts per second. Calculate the count rate for the rock. Countrate=1335persecond (b) ) A householder is worried about the radiation emitted by the granite worktop in his kitchen. 1 kg of granite has an activity of 1250 Bq. The kitchen worktop has a mass of 180 kg. Calculate the activity of the kitchen worktop in Bq.

Question

Q2. A teacher used a Geiger-Muller tube and counter to measure the number of counts in 60 seconds for a radioactive rock. (a) The counter recorded 819 counts in 60 seconds. The background radiation count rate was 0.30 counts per second. Calculate the count rate for the rock. Countrate=1335persecond (b) ) A householder is worried about the radiation emitted by the granite worktop in his kitchen. 1 kg of granite has an activity of 1250 Bq. The kitchen worktop has a mass of 180 kg. Calculate the activity of the kitchen worktop in Bq.

Answer 1

## Part (a):- Background radiation over 60 seconds =

counts.- Net counts =

counts.- Count rate =

counts per second.## Part (b):- Activity =

Bq.

Answer 2

## Part (a):### Step 1: Identify the total counts and time.- Total counts recorded: 819 in 60 seconds.- Background radiation: 0.30 counts per second.### Step 2: Calculate the net count rate for the rock.- Subtract the background radiation from the total counts to get the net counts.- Background radiation over 60 seconds =

.### Step 3: Use the formula for count rate.- **

**.## Part (b):### Step 1: Identify given values.- Activity of 1 kg of granite: 1250 Bq.- Mass of the kitchen worktop: 180 kg.### Step 2: Calculate the total activity of the worktop.- **

**.

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