diff --git a/physics/mass_energy_equivalence.py b/physics/mass_energy_equivalence.py
new file mode 100644
index 000000000000..3139225a7ca7
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+++ b/physics/mass_energy_equivalence.py
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+"""
+Einstein's E=mc^2: Mass-energy interchange,
+even in motion. Small rest mass yields big
+energy,invariant across frames. Lost energy
+means lost mass.Einstein's 1905 theory, vital
+in nuclear and particle physics.
+
+Reference:Wikipedia
+"""
+
+
+def energy_mass_equivalence(mass: float) -> float:
+    """
+    Converted mass into corresponding energy
+
+    For example:
+    >>> energy_mass_equivalence(2.1)
+    189000000000000000.00
+    >>> energy_mass_equivalence(3)
+    270000000000000000.00
+    >>> energy_mass_equivalence(3.123)
+    281070000000000032.00
+    >>> energy_mass_equivalence(1)
+    90000000000000000.00
+    """
+    energy = mass * ((3 * 10**8) ** 2)
+    return f"{energy:.2f}"
+
+
+# test
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod(name="mass_energy_equivalence")