Units & Dimensions

JEE Main level, single correct, medium

127 of 149

Question 127 of 149

The characteristic distance at which quantum gravitational effects are significant, the Planck length, can be determined from a suitable combination of the fundamental physical constants G,h\mathrm{G}, \mathrm{h} and c\mathrm{c}. Which of the following correctly gives the Planck length?

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Answer: (B) (Ghc3)12\left(\frac{\mathrm{Gh}}{\mathrm{c}^3}\right)^{\frac{1}{2}}

Plank length is a unit of length,
lp=1.616229×10−35 mlp=hGc3\begin{aligned} &l_p=1.616229 \times 10^{-35} \mathrm{~m} \\ &l_p=\sqrt{\frac{h G}{c^3}} \end{aligned}

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