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3 years ago

What is the wavelength of an ekectromagnetic wave that has a frequency of 40,000 hz? the speed of light is 3x10^8 m/s?

Physics

1 answer:

ehidna [41]3 years ago

7 0

Solution
As,
speed=frequency × wavelengths
so,
wavelength=speed/frequency
=3×10^8/40000
=7500m

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balu736 [363]

Explanation:

It is given that,

Speed of the person, v = 3 mile/hr = 1.34 m/s

Speed of the truck, v' = 65 mile/hr = 29.05 m/s

(a) Since, $\beta =\dfrac{v}{c}$

For the person, $\beta =\dfrac{1.34}{3\times 10^8}=4.47\times 10^{-9}$

For the truck, $\beta =\dfrac{29.05}{3\times 10^8}=9.68\times 10^{-8}$

(b) The relativistic factor is given by :

$\gamma=\dfrac{1}{\sqrt{1-\beta^2}}$

For very small velocity, $\beta$

$\gamma=(1-\beta ^2)^{-1/2}\approx 1+\dfrac{1}{2}\beta ^2$

$\gamma-1=\dfrac{\beta^2}{2}$

For the person :

$\gamma-1=\dfrac{(4.47\times 10^{-9})^2}{2}=9.99\times 10^{-18}$

For the person :

$\gamma-1=\dfrac{(9.68\times 10^{-8})^2}{2}=4.68\times 10^{-15}$

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3 years ago

The temperature of 2.0 g of helium is increased at constant volume by ΔT. What mass of oxygen can have its temperature increased

gavmur [86]

Answer:

m = 9.6 g

Explanation:

Thermal energy given to helium gas at constant volume is given as

$Q = nC_v \Delta T$

so here we have

$C_v = \frac{3}{2}R$

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$n = \frac{2}{4} = 0.5$

so we have

$Q = \frac{3}{2}R(0.5)\Delta T$

now we know that

for oxygen gas we have

$C_v = \frac{5}{2}R$

for same amount of heat we have

$Q = nC_v \Delta T'$

$\frac{3}{2}R(0.5)\Delta T = \frac{m}{32} (\frac{5R}{2}) \Delta T$

$m = \frac{0.75 \times 32}{2.5}$

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Answer:

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Generally potential energy is a the varies directly with the height according to this formula

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