Two very long, straight, parallel wires carry currents that are directed perpendicular to the page as shown in Figure 7. Wire 1 carries a current I1 into the page (in the –z direction) and passes through the x axis at x = +a. Wire 2 passes through
the x axis at x = –2a and carries an unknown current I2. The total magnetic field at the origin due to the current-carrying wires
has the magnitude 2μ0I1/(2πa). The current I2 can have either of two possible values. (a) Find the value of I2 with the smaller
magnitude, stating it in terms of I1 and giving its direction. (b) Find the other possible value of I2.​

The particle in a two-dimensional well is a useful model for the motion of electrons around the indole ring (3), the conjugated cycle found in the side chain of tryptophan. we may regard indole as a rectangle with sides of length 280 pm and 450 pm, with 10 electrons in the conjugated p system. as in case study 9.1, we assume that in the ground state of the molecule each quantized level is occupied by two electrons. (a) calculate the energy of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels. 9.27 electrons around the porphine ring (4), the conjugated macrocycle that forms the structural basis of the heme group and the chlorophylls. we may treat the group as a circular ring of radius 440 pm, with 20 electrons in the conjugated system moving along the perimeter of the ring. as in exercise 9.26, assume that in the ground state of the molecule quantized each level is occupied by two electrons. (a) calculate the energy and angular momentum of an electron in the highest occupied level. (b) calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels.

Could someone . i have tried to solve myself but my calculation is off

Question part points submissions used suppose that 2 j of work is needed to stretch a spring from its natural length of 26 cm to a length of 36 cm. (a) how much work is needed to stretch the spring from 28 cm to 32 cm? (round your answer to two decimal places.)