Converting Units: A Beginner's Guide

  • Thread starter Thread starter lb beatz
  • Start date Start date
  • Tags Tags
    Units
AI Thread Summary
Unit conversion, particularly in physics, often requires understanding the specific definitions of units like electronvolts (eV) without relying on joules for explanation. Participants emphasize the importance of attempting a solution before seeking help, as this fosters learning and clarifies misunderstandings. Hints and guidance are offered rather than complete solutions to encourage independent problem-solving. The discussion highlights the relevance of equations in unit conversion processes. Understanding the context and definitions of units is crucial for successful conversions.
lb beatz
Messages
1
Reaction score
0
Homework Statement
Suppose that certain food was irradiated with an electron beam of kinetic energy 10 MeV. (a) What is the voltage needed for an 'electron gun' to give this kinetic energy to an electron from rest?
Relevant Equations
E = 10 MeV ---> transform to joule

E = e.U ---> ddp ( voltage)
How can I be doing this conversion, could someone explain to me?
 
Physics news on Phys.org
Welcome to Physics Forums :welcome:

We can't provide the full solution for your homework, however we can provide you with hints towards the solution and warn you where you go wrong, provided that you write some attempt for the solution with a post of yours.

You don't have to transform the energy to joules to answer this.

Your second equation is quite relevant. Do you know how the unit of eV is defined? (don't give me a definition through the unit of Joule)
 
Reply
  • Like
Likes Keith_McClary and Orodruin

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Conversion factor when converting from SI to natural units
Replies
1
Views
798
The behaviour of an uncharged dielectric particle in a capacitor
Replies
2
Views
1K
How Can I Solve Question Type: "With Magnitude and Unit Vectors"?
Replies
14
Views
2K
Question in Thermal Physics (Van der Waals' Equation)
Replies
6
Views
2K
I Unit Conversions of Force: How to Convert Between Different Units of Force?
Replies
4
Views
1K
Convert J/mol k into atm cm^3/mol k
Replies
6
Views
7K
Question about this unit conversion principle (multiplying by "1")
Replies
16
Views
1K
Can Mixed Units in Ratios Be Converted and Used Accurately in Calculations?
Replies
6
Views
1K
Unit conversions involving Pascals
2
Replies
67
Views
6K
Writing a vector parallel and normal to a unit vector ##\hat n##
Replies
26
Views
1K

Hot Threads

Recent Insights

Back
Top