The Enigmatic

Doppler Effect Numerical Problem | Easy Solution | Physics Wallah

Question:
Volt/Meter is the Unit Of.....
A---Potential
B---Work
C---Force
D---Electric Field

Answer in Comment Section After 24 hours!!!

Which One of the following Quantities is equal to Joule x ohm/Volt x Second.

1---Amphere
2---Volt
3---Watt
4---Tesla

Answer in Comment Section After 24 Hours

The percentage error in the measurement of mass and speed are 2% and 3% respectively. Percentage error in the measurement of kinetic energy is?

A------11%
B------8%
C------5%
D------1%

Answer in Comment Section!

Question:
Uncertainty Recorded in the Radius of Sphere is 1.6%.The Uncertainty in the Area of Sphere is?

A------4.8%
B------3.2%
C------1.6%
D------0.8%

Answer in Comment Section.

Why is only the vertical component used to find the time of flight for an object in projectile motion?

Answer in Comments

If a percentage error in the measurement of mass and the momentum of an object are 2% and 3% respectively, what is the maximum % error in the calculated value of its kinetic energy?
A: 6%
B: 7%
C: 9%
D: 10%

Answer in Comment Section

Download all useful materials related to medical college admissions tests here.

Question: A travelling wave on a rope has a frequency of 2.5 Hz. If the speed of the wave is 1.5m/s, what are its period and wavelength?





Answer

The period is easy:

Period = T = 1/f = 1/frequency

The unit Hz about 50–60 years ago was simply cycles/second.

Hertz was a Physicist who worked on waves, so he was honored in this way.

T = 1 / 2.5 Hz = 0.4 seconds
(the term cycle is not really a unit)

The relationship between wavelength, frequency, and velocity is

V = wavelength*frequency

V= lambda/f,

so

lambda = v/f = (1.5 m/s) / 2.5 Hz = 0.6 m

Question: The speed of light in a certain material is 1.5 X 10^8 m/s. What is the wavelength of this light if the frequency of the source is 7.5 X 10^14 Hz?





Answer

We know that frequency of the photons remains the same no matter if it moves from one medium to another.

Velocity, v = 1.5 x 10⁸ m/s

Frequency, f = 7.5 x 10¹⁴ Hz

Wavelength, λ = ? (To be calculated)

We know that, v = λf

λ = v/f = (1.5 x 10⁸)/(7.5 x 10¹⁴)

= 2 x 10-⁷m

= 200nm

Therefore the wavelength of the light emitted by the source in that medium is 200nm

What is the wavelength (in nm) and the frequency of a photon with an energy of 8.2 x 10^-19 J?





Answer

The wavelength is found by using the equation

E= hc/wavelength

where

E= energy of the photon= 8.2x10^-19J

h= Planck’s constant=6.63x10^-34Js

c= speed of light in a vacuum= 3.0x10^8m/s=3.0x10^17nm/s

wavelength of photon= unknown

solving the equation for wavelength gives

wavelength = hc/E
= (6.63x10^-34)*(3.0x10^17)/(8.2x10^-19)

the wavelength of the photon= (2.0x10^-16)/(8.2x10^-19)=2.4x10^2 nm

The frequency of the photon is found by using the equation

E= hf

solving for f gives

f= E/h

f= (8.2x10^-19)/6.63x10^-34

= 1.24x10^15s^-1

What is the Energy of a photon of wavelength 600 nm (or 600 x 10-9 m)?

Answer:

E = hc/λ

where E = energy, h = Planck's constant, c = speed of light, and λ = wavelength.

Known and Unknown

E = ?

h = 6.626×10⁻³⁴Js

c = 3.00 × 10⁸ m/s

λ = 600 × 10⁻⁹ m

Calculate E.

E = (6.626×10⁻³⁴Js × 3.00 × 10⁸ m/s)/(600 × 10⁻⁹ m)

E= 3.31 × 10⁻¹⁹ J