Need 1.5m wire carries a 7 a current when a potential difference of 86 v is applied. what is the resistance of the wire?

R = 9.7 Ω

length of wire L = 1.5 m  

 I = 7 A

V = IR

R = V/I

R = 68/7

R = 9.7 Ω

Resistance = (voltage) / (current)

Resistance = (86 volts) / (7 Amperes)

Resistance = (86/7) (volt/Ampere)

Resistance = 12.3 ohms

Since you told us the voltage across the wire and the current through it, we don't need to know its length.  That information doesn't help us.

atomic = no of protons.

mass number-atomic number = neutron number

no. dot product   =0 when vecs at right angles