Power delivered to a resistor

Four resistors are connected to a battery with a terminal voltage of 15 V, as shown in attached figure. Determine the power delivered to R2. (R1 = 20 ohm;, R2 = 45 ohm)

DC Circuits

Assume that the length of an axon membrane of about 10 cm is excited by an action potential (length excited = nerve speed x pulse duration = 50 m/s x 2.0 ms = 10 cm). In the resting state, the outer surface of the axon wall is charged positively with K+ ions and the inner wall has an equal and opposite charge of negative organic ions, as shown in Figure P18.41. Model the axon as a parallel-plate, capacitor and take C = κε A/d and Q = CΔV to investigate the charge as follows: Use typical values for a cylindrical axon of cell thickness d = 1.2 x 10-8 m, axon radius r = 12.0 µm, and cell-wall dielectric constant κ = 2.9. 1.) How much energy does it take to rest... click for more

DC Circuits

Using the attached figure and the fact that it takes 8.0 x 10-12 J to raise the potential of the inner axon wall to +30 mV from -70 mV and another 4.3 x 10-11 J to restore the inner wall of the axon to -70 mV from +30 mV, find the power supplied to the axon per action potential. _____________W

SHOCKLYE EXPERIMENT

i need help with this problem...some detail explanation.

shockley experiment

please help me with this.