Which of the following has the highest atomic size ? a beryllium b strontium c barium d radium

D. Radium

Explanation: The atomic size of an atom increases when it moves down in a group. The number of energy levels increases due to the increase number of electrons. This contributes to the increase in atomic size since energy orbitals becomes farther from the nucleus.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

layers of the earth affect the waves and these effects are seen on instruiments such as seimometers