The de-Broglie wavelength of an electron in 4th orbit is (where $r=$ radius of the 1st orbit)
$2 \pi r$
$4 \pi r$
$8 \pi r$
$16 \pi r$
An electromagnetic wave,whose wave normal makes an angle of $45^{\circ}$ with the vertical,is travelling in air and strikes a horizontal liquid surface.While travelling through the liquid,it gets deviated by $15^{\circ}$ .If the speed of electromagnetic wave in air is $3 \times 10^8 \mathrm{~m} / \mathrm{s}$ ,then the speed of electromagnetic wave in the liquid will be
$\frac{\sqrt{2}}{3} \times 10^8 \mathrm{~m} / \mathrm{s}$
$1.5 \times 10^8 \mathrm{~m} / \mathrm{s}$
$2.1 \times 10^8 \mathrm{~m} / \mathrm{s}$
$2.5 \times 10^8 \mathrm{~m} / \mathrm{s}$
The circuit has two oppositely connected ideal diodes in parallel as shown in the figure.What is the current flowing in the circuit?

1.33 A
1.71 A
2.00 A
2.31 A
2 moles of an ideal gas with $\frac{C_p}{C_v}=\frac{5}{3}$ are mixed with 3 moles of another ideal gas with $\frac{C_p}{C_v}=\frac{4}{3}$ .The value of $\frac{C_p}{C_v}$ for the mixture is
1.5
1.42
1.48
1.6
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