A photon has energy of $1 \times 10^{18} \text{ eV}$ - AQA - A-Level Physics - Question 8 - 2020 - Paper 1
Question 8
A photon has energy of $1 \times 10^{18} \text{ eV}$.
An object of mass 0.03 kg has kinetic energy equal to the energy of the photon.
What is the speed of the ob... show full transcript
Worked Solution & Example Answer:A photon has energy of $1 \times 10^{18} \text{ eV}$ - AQA - A-Level Physics - Question 8 - 2020 - Paper 1
Step 1
Calculate the kinetic energy
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Answer
The kinetic energy (KE) of the object is equal to the energy of the photon, which is given as:
KE=1×1018 eV.\
To convert eV to Joules, multiply by the conversion factor 1 eV=1.6×10−19 J. Thus,
KE=1×1018 eV×1.6×10−19 J/eV=1.6×10−1 J.
Step 2
Apply the kinetic energy formula
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Answer
The formula for kinetic energy is given by:
KE=21mv2,
where m is the mass and v is the speed of the object. Rearranging this formula to solve for speed gives:
v=m2KE.
Substituting in the values:
v=0.03 kg2×1.6×10−1 J.
Step 3
Calculate the speed
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Answer
v=0.030.32=10.6667≈3.26 m/s.
Rounding to a reasonable figure gives approximately 3 m/s. Therefore, the speed of the object is approximately 3 m/s.
