PART - 1 CH - 1 Units and Measurements — Physics STD 11 Science — Question
Rajasthan BoardEnglish MediumSTD 11 SciencePhysicsPART - 1 CH - 1 Units and Measurements2 Marks
Question
Convert 1 Joule of energy into CGS system.
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Answer
The unit of energy is SI system is Joule and that is in the CGS system is erg. Dimensional formula of energy $=\left[ M ^1 L^2 T^{-2}\right]$ Here, $a=1, b=2, c=-2$ S.I. System $M _1=1 kg$ $L _1=1 m$ $T _1=1 s$ $n _1=1$ Joule C.G.S. System $M _2=1 gm$ $L _2=1 cm$ $T _2=1 s$ $n _2=$ ? $\begin{aligned} n_2 & =n_1\left[\frac{M_1}{M_2}\right]^a\left[\frac{L_1}{L_2}\right]^b\left[\frac{T_1}{T_2}\right]^c \\ & =1\left[\frac{1 kg}{1 g}\right]^1\left[\frac{1 m}{1 cm}\right]^2\left[\frac{1 s}{1 s}\right]^{-2} \\ & =1\left[\frac{1000 g}{1 g}\right]^1\left[\frac{100 cm}{1 cm}\right]^2\left[\frac{1 s}{1 s}\right]^{-2} \\ & =1 \times 10^3 \times\left(10^2\right)^2=10^3 \times 10^4=10^7 \end{aligned}$ Hence, 1 Joule $=10^7$ erg.
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