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An electron falling from one energy level to another emits a photon of wavelength 550nm. What is the difference between the two energy levels?

The key equation is that of the energy of a photon. E = hc/ λ​ Using λ​ = 550nm gives E = 3.61x10^-19J (Remember that a nanometer is 1x10^-9 m ). Using the conservation of energy, the energy of this photon m...
JL
Answered by Jamie L. • Physics tutor
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A space probe of mass 1000kg, moving at 200m/s, explosively ejects a capsule of mass 300kg. The speed of the probe after the explosion is 250m/s. What is the velocity of the capsule?

To solve this problem, we must apply conservation of momentum. Even though there is kinetic energy being added to the probe-capsule system by the explosion, momentum will always be conserved if there are no ...
AS
Answered by Alexander S. • Physics tutor
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How does energy flow from voltage source to resistor in a simple DC circuit?

Let us consider a simple dc circuit consisting of a battery and a resistor connected by ideal wires. As we know, current starts to flow thorugh the resistor and heat is generated as a result of this current ...
SH
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Do batteries contain current, which comes out when they are in a circuit?

No; this is a common misconception! Batteries store energy, which is used to push electrons (charges) around a circuit. The flow of electrons is called current. As the electrons flow through the circuit they...
SS
Answered by Samuel S. • Physics tutor
4356 Views

If one proton is travelling through space at 0.3c, what is it's kinetic energy in MeV?

We know the formula for kinetic energy is KE = (1/2)mv 2 . If we know that c, the speed of light, is 3x10 8 ms -1 (you will be given this value in your Data & Formula books in the exam) and the proton is...
OB
Answered by Oisin B. • Physics tutor
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