Which of the following is a correct<br> definition of the word "contingencies"?

A boat moves through the water of a river at 10m/s relative to the water, regardless of the boat ‘s direction . If the water in

katen-ka-za [31]

Answer:

The appropriate solution is "61.37 s".

Explanation:

The given values are:

Boat moves,

= 10 m/s

Water flowing,

= 1.50 m/s

Displacement,

d = 300 m

Now,

The boat is travelling,

= $10+1.50$

= $11.5 \ m/s$

Travelling such distance for 300 m will be:

⇒ $v = \frac{d}{t} \ sot \ t$

$=\frac{d}{v}$

On putting the values, we get

$=\frac{300}{11.5}$

$=26.08 \ s$

Throughout the opposite direction, when the boat seems to be travelling then,

= $10-1.50$

= $8.5 \ m/s$

Travelling such distance for 300 m will be:

⇒ $v=\frac{v}{t} \ sot \ t$

$=\frac{d}{v}$

On putting the values, we get

$=\frac{300}{8.5}$

$=35.29 \ s$

hence,

The time taken by the boat will be:

= $26.08+35.29$

= $61.37 \ s$

8 0

3 years ago

A hydrogen atom in the n=7 state decays to the n=4 state. what is the wavelength of the photon that the hydrogen atom emits? use

frez [133]

A hydrogen atom in the n=7 state decays to the n=4 state. The wavelength of the photon that the hydrogen atom emits is 4592.59nm.

The Energy of photon is the energy possessed by a photon when it moves from a high energy level to a low energy level. It emits a photon of a certain wavelength. The following relation can be used to find out the relation between the energy levels and the energy possessed:

E = 13.6 × Z² (1/n₂² - 1/n₁²) eV

where, n₁ is the initial energy level i.e. n₁ =7

n₂ is the higher energy level i.e. n₂ = 4

E is the energy possessed

Z is the atomic number, Z = 1 for H-atom

Subsituting in above equation,

E = 13.6 (1/16 - 1/49) eV

E = 0.27 eV

We know that,

E = hc / λ

where, h is Planck constant

c is speed of light