Physics · Work, Power & Energy
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A neutron travels a distance of 12 m in a time interval of 3.6 x 10 - 4s. Assuming its speed was constant, find its kinetic energy. (take 1.7 x 10 - 27 kg is the mass of neutron)
- A
3.14 eV
- B
5.78 eV
- C
7.71 eV
- D
8.89 eV
- E
9.96 eV
First, calculate the speed of the neutron using the formula speed = distance/time. Here, the speed is 12 m / (3.6 x 10-4 s) = 3.33 x 104 m/s.
Next, use the formula for kinetic energy: K.E = ½ mv2. Substituting the values, we have:
K.E = ½ (1.7 x 10-27 kg) x (3.33 x 104 m/s)2 = 93 x 10-20 J
Convert this energy from Joules to electronvolts (eV) using the conversion factor 1 eV = 1.6 x 10-19 J:
K.E = (93 x 10-20 J) / (1.6 x 10-19 J/eV) = 5.78 eV.
Thus, option B is correct. The other options result from incorrect calculations or conversion errors.
This option is incorrect. Revisit the calculation of kinetic energy using the correct speed.
This is the correct answer. The speed and subsequent kinetic energy calculations are accurate.
This option is incorrect. Ensure that the speed is calculated correctly before converting to kinetic energy.
This option is incorrect. Double-check the conversion from Joules to electronvolts.
This option is incorrect. Verify that you have used the correct mass and speed in your calculations.
Tagged under Physics · Work, Power & Energy · 2015