The energy equivalence of 1 eV is
1.602× 10-19 J
Electron Volt (eV) Definition
The electron volt, commonly abbreviated as eV, is a fundamental unit of energy widely used in various branches of physics, especially in atomic, nuclear, and particle physics. It is precisely defined as the amount of kinetic energy gained by a single electron when it is accelerated from a state of rest through an electric potential difference of one volt in a vacuum.
Energy Equivalence of 1 eV to Joules
To determine the energy equivalence of 1 eV in Joules (J), we can use the relationship between work (or energy), charge, and potential difference. This relationship is a cornerstone of electromagnetism and is essential for understanding energy conversions at the subatomic level.
- The work done (W) on a charge (q) as it moves through a potential difference (V) is given by the formula:
- $$W = qV$$
- In the context of an electron volt, the work done on the electron is the energy it gains.
- The fundamental charge of a single electron (denoted as 'e') is a known physical constant:
- $$e = 1.602 \times 10^{-19} \text{ Coulombs (C)}$$
- By definition, for 1 electron volt, the potential difference (V) is 1 Volt (V).
Therefore, the energy equivalence of 1 eV can be calculated by substituting these values into the formula:
- $$1 \text{ eV} = (\text{charge of 1 electron}) \times (1 \text{ Volt})$$
- $$1 \text{ eV} = (1.602 \times 10^{-19} \text{ C}) \times (1 \text{ V})$$
- Since 1 Joule (J) is dimensionally equivalent to 1 Coulomb-Volt (C·V):
- $$1 \text{ eV} = 1.602 \times 10^{-19} \text{ J}$$
Comparing Options for 1 eV Equivalence
Let's evaluate the given options based on our understanding of the electron volt and its conversion to Joules:
| Option | Value | Analysis |
|---|---|---|
| 1 | $6.606 \times 10^{-34} \text{ J}$ | This value is numerically very close to Planck's constant ($h \approx 6.626 \times 10^{-34} \text{ J s}$), which is a unit of action or angular momentum, not the energy equivalence of 1 eV. |
| 2 | $931 \times 10^{6} \text{ J}$ | This value is significantly larger and is related to the energy equivalence of mass, specifically 1 atomic mass unit (amu) which is approximately 931.5 MeV (Mega-electron Volts) or $931.5 \times 10^6$ eV, not Joules directly, and certainly not 1 eV. |
| 3 | $1.602 \times 10^{-19} \text{ J}$ | This value precisely matches the calculated energy equivalence of 1 eV, which is derived from the elementary charge of an electron. This is the correct conversion factor. |
| 4 | $6.626 \times 10^{-34} \text{ J}$ | This value is Planck's constant, $h$, which has units of Joules-seconds (J·s). While it's a fundamental constant in quantum mechanics, it does not represent the energy of 1 eV. |
Therefore, based on the definition and calculation, the energy equivalence of 1 eV is $1.602 \times 10^{-19}$ Joules.
Important Questions from Work
A body of mass 100 kg rests on a horizontal plane, the value of coefficient of friction between the body and plane being 0.025. Find the work done in moving the body through a distance of 10 metres along the plane.
A load of 16.5 kg is lifted through a height of 3.4 metres. Find the work done in kg metre.
______ efforts are where our eyes direct the movement of our bodies.
Task simplifications represent _______ work methods.
A body of mass 100 kg rests on a horizontal plane, the value of coefficient of friction between the body and plane being 0.025. Find the work done in moving the body through a distance of 10 metres along the plane.
