Two small, identical conducting spheres repel each other with a force of 0.025 N when they are 0.55 m apart. After a conducting wire is connected between the spheres and then removed, they repel each other with a force of 0.070 N. What is the original charge on each sphere? (Enter the magnitudes in C.) smaller value ? C
larger value ? C

Aspecimen of oil having an initial volume of 580cm^3 is subjected to a pressure increase of 4.0 mpa, and the volume is found to decrease by 0.40 cm^3. (a) what is the bulk modulus of the material? (b) what is the compressibility of the material?

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?

What is the role of lenses in microscopy?