4 In the circuit of figure 1, the cell E1 has an emf of 15V and internal resistance of 2; the cell E2 has emf of 6V and internal resistance of 3; and the cell E3 has emf of 4V

and internal resistance of 1. In the circuit R1=4, R2=3 and R3=2

Determine the currents I1, I2, and I3 [5 marks]

Figure 1

An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. the company took a random sample of 27 cars driven by men on a highway and found the mean speed to be 72 miles per hour with a standard deviation of 2.2 miles per hour. another sample of 18 cars driven by women on the same highway gave a mean speed of 68 miles per hour with a standard deviation of 2.5 miles per hour. assume that the speeds at which all men and all women drive cars on this highway are both approximately normally distributed with unknown and unequal population standard deviations.

Light from the sun reaches the earth in 8.3 minutes. the velocity is 3.00 x 10^8 m/s. how far is earth from the sun? i know how to get to d = (3 x 10^8 m/s)(498 sec). i just don't know how to get from there to the answer being 1.5 x 10^11 m.

If an atom contains 11 protons in its nucleus, predict the element with the atomic number and electronic configuration. will the number of electrons remain the same during the chemical reaction in such an atom? explain.