ten positively charged particle are fixed on the X-axis at points x=10cm,20cm,30cm...........,100cm.the first particle has a charge 1.0(1/100000000)C,the second 8(1/100000000),the third 27(1/100000000)C and so on.find the magnitude of the electric force acting on a 1C charge placed at the origin.

Simply apply kq/(r^2) formula and solve it futher taking distance in metre and for simplicity make the charge in power of 10.Now as all the charges are of same sign therefore all the electric feild will add up.Now take k common from each term .Now resolve the left term you will found a pattern like K (1+2+3+4+5+6+7+8+9+10)×10^-6Now apply sum of first n natural number and solve futhur u will get ans 495×10^3