# Search results

1. ### Uncertainty calculation

Homework Statement My homework question says: the uncertainty in length 1 is +/- 0.1 and in length 2 is +/- 0.1 : calculate the percentage uncertainty in V where V L1-L2 is 30 Homework Equations V= (1/(L1-L2))^0.5 where L is the length[/B] The Attempt at a Solution So what I did was...
2. ### Fiducial marker in SHM systems

Homework Statement Where would be the perfect place to place a fiducial marker in a: mass on a spring system (vertical) and a simple pendulum? Homework Equations The Attempt at a Solution My teacher told me that for a simple pendulum it would be below the bob at equillibrium position...
3. ### Capacitor discharge

Could someone explain to me how a capacitor discharges through another capacitor of different capacitance. Why does the voltage on the second capacitor have to equal the voltage on the first capacitor after the discharge. Please explain the concept to me in simple terms, do not go into...
4. ### Electromagnetic induction of a wire in a complete circuit

Say for you had a wire in a complete circuit inside a magnetic field (pointing inwards) perpendicular to the wire. You move the wire across (to the right) , cutting lines of flux, this induces a current in the wire. The induced current acts upwards using the dynamo rule (thumb is motion...
5. ### Geiger counters and activity

I'm doing high school physics and if a question says something like: A radioactive source gives count rate of 110 counts per second Can you say that the ACTIVITY is also 110 bq? My second question is how would a gieger counter detect gamma radiation? It is the least ionising of all three...
6. ### Definition of gravitational potential

Homework Statement The definition of gravitational potential at a point in my textbook is "the work done per kg to move a small test mass from infinity to that point" I am having difficulty grasping this concept, how is work done bringing an object closer to earth?? shouldn't work be done...
7. ### Measuring redshift from type 1a supernova

I know that you can measure redshift from stars by looking at the shift in there balmer lines or more generally there line absorption spectra and seeing how far these lines have shifted from actual balmer lines or line absorption spectra of the same elements on earth. But how would you...
8. ### Absolute magnitude and luminosity

Do two stars of the same absolute bolometric magnitude have the same absolute visual magnitude? If this is true; does this mean that two stars with the same power output have the same have the same bolometric magnitude and therefore same visual magnitude?
9. ### Difference in power and absolute magnitude of a star

My physics book mentions that a stars luminosity is its total power output at all wavelengths and that absolute magnitude is defined as inherent brightness and NOT luminosity. It then mentions that two stars of the same power output have the same absolute magnitude. Since luminosity is the...