Question

One milligram of matter convert into energy will give
(a) 90 joule (b) 9 × 10³ joule
(c) 9 × 10⁵ joule (d) 9 × 10¹⁰ joule

Answer 1

Given :

▪ Mass of matter = 1mg

To Find :

▪ The energy associated with matter..

Concept :

➡ According to Albert Eindtein, mass and energy are inter-convertible. In 1905, he established the mass energy equivalence. The energy associated with mass m is given by

$\bigstar\:\underline{\boxed{\tt{\large{\red{E=mc^2}}}}}$

Calculation :

$\implies\sf\:E=mc^2\\ \\ \implies\sf\:E=(1mg)(3\times 10^8)^2\\ \\ \implies\sf\:(10^{-6}\:kg)(9\times 10^{16})\\ \\ \implies\underline{\boxed{\bf{\orange{E=9\times 10^{10}J}}}}\:\gray{\bigstar}$

☢ Option-D is correct ✔

Answer 2

$\bold{\bf{\red{E=mc^2}}}$

where ,

• E denotes energy
• m denotes mass or matter
• c denotes speed of light

Here , mass , m = 1 mg = 10⁻⁶ kg

          c = 3 * 10⁸ m/s

$\implies \bold{E=mc^2}\\\\\implies \bold{E=10^{-6}*(3*10^8)^2}\\\\\implies \bold{E=10^{-6}*9*10^{16}}\\\\\implies \bold{\bf{\blue{E=9*10^{10}\;Joules}}}$

Hence option (d) is correct