A charge q moves from point A to point B in an electric field. The potential energy of the charge at point A is 5.6 × 10-10 joules and that at point B is 2.3 × 10-10 joules. If the kinetic energy at point A is zero, what is the kinetic energy at point B?
5.6 × 10-12 joules
1.3 × 10-12 joules
2.3 × 10-12 joules
3.3 × 10-10 joules
5.6 × 10-10 joules

Respuesta :

Answer:

3.3 × 10-10 joules

Explanation:

For the law of conservation of energy, the loss in electrical potential energy of the charge must be equal to the gain in kinetic energy of the particle:

[tex]U_A-U_B = K_B-K_A[/tex]

the kinetic energy of the charge at point A is zero: [tex]K_A=0[/tex], so we can immediately find the kinetic energy of the charge at point B:

[tex]K_B=U_A-U_B=5.6\cdot 10^{-10} J-2.3\cdot 10^{-10} J=3.3\cdot 10^{-10} J[/tex]

Answer: Option (d) is the correct answer.

Explanation:

According to work energy theorem, total work done on an object equals to the change in objects kinetic energy and change in potential energy.

Mathematically,    [tex]\Delta Kinetic energy = -\Delta Potential energy[/tex]

It is given that potential energy at point A is [tex]5.6 \times 10^{-10}[/tex] joules and at point B it is [tex]2.3 \times 10^{-10}[/tex] joules.

Also, kinetic energy at point A is zero and at point B we will calculate the kinetic energy as follows.

                [tex]\Delta Kinetic energy = -\Delta Potential energy[/tex]

                [tex]K.E_{B} - K.E_{A}[/tex] = [tex]-[P.E_{B} - P.E_{A}][/tex]

                [tex]K.E_{B} - 0[/tex] = [tex]-[2.3 \times 10^{-10} - 5.6 \times 10^{-10}][/tex]

                                   = [tex]-( -3.3 \times 10^{-10})[/tex] joules

                                   = [tex]3.3 \times 10^{-10}[/tex] joules

Thus, we can conclude that kinetic energy at point B is [tex]3.3 \times 10^{-10}[/tex] joules.

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