Ahh * photons.
And yes, this is the problem.
Suppose a blackbody emits photons strongly with a frequency near 4 GHz. What is the photon energy? And then i found the value that i stated above (in J), which is correct.
The question then asks for the temperature of the black body and that's...
Homework Statement
It emits protons with a frequency of 4 GHz, and has a photon energy of 2.65E-24 J.
I tried to use the formula lambda=c/f=vT, but i am somehow getting a negative answer which doesn't make sense when trying to find temperature in (K).
Any help is greatly appreciated.
Homework Statement
A spaceship moves past you at speed v. You measure the ship to be 300 m long, whereas an astronaut on the ship measures a length of 445 m. Find v.
The Attempt at a Solution
I tried to substitute my numbers into L1=Lsqrt(1/(v^2/c^2)) and keep getting a negative wrong...
Homework Statement
X-rays are electromagnetic waves with very short wavelengths. Suppose an X-ray has an wavelength of 0.126 nm. What is its frequency?
The Attempt at a Solution
I tried (1)/(1.26E-10)=7936507937, which is in Hz, but they want it to GHz, so i converted it and got 7.94 GHz...
Homework Statement
Because of the 2 wires in the figure,
For what value of the ratio I1/I2 is the magnetic field zero at the point A? point B? point C?
Homework Equations
http://tinypic.com/r/5otweg/7
The Attempt at a Solution
I honestly have no idea where to start with this problem, any...
Homework Statement
A 10 cm long solenoid with 241 turns and radius R = 3.00 cm has a current flowing through it of Io = 200 mA. What is the magnetic field strength inside the solenoid (in T)?
The Attempt at a Solution
So i know i have to use the formula B = (uo)(n)(Io)
uo = a constant 1.257...
Homework Statement
A wire has a diameter of 1.51 mm and a length of 32.7 m, and is found to have a resistance of 1.5 capital omega. What is the resistivity of the wire?
Homework Equations
The Attempt at a Solution
R=qL/A
R=.0051/2=7.55E-4
L=32.7
A = ?
How do i find A to...
Homework Statement
Two resistors with R1 = 1755 omega and R2 = 4020 omega are connected in parallel. The battery emf is large epsilon = 15 V.
What is the current through resistors R1?
What is the current through resistors R2?
Homework Equations
The Attempt at a Solution
I...
Homework Statement
For the resistance versus temperature graph below, find (a) the resistance at T = 20°C and (b) the temperature coefficient of resistance alpha .
http://tinypic.com/r/jhufkn/7
I don't know if the graph is showing up or not, it isn't for me... so here's the link...
Homework Statement
A small, plastic sphere of mass m = 126 g is attached to a string as shown in the figure.
There is an electric field of 151 N/C directed along the + x axis. If the string makes an angle 30 with the y axis when the sphere is in equilibrium, what is the charge on the...
Homework Statement
When a third charge is placed at the origin, it is found that the force on it is zero. Find alpha?
Two charges Q and 5Q are located as shown in the figure below.
https://chip.physics.purdue.edu/protected/GiordanoEMimg/chapter17/17prob16.jpg
If possible, please...