Answer:
oxygen silicon aluminun iron
Answer:

Explanation:
Using the tension in the spring and the force of the tension can by describe by
T = kx
, T = mg
Therefore:

With two springs, let, T1 be the tension in each spring, x1 be the extension of each spring. The spring constant of each spring is 2k so:


Solve to x1





let us consider that the two charges are of opposite nature .hence they will constitute a dipole .the separation distance is given as d and magnitude of each charges is q.
the mathematical formula for potential is 
for positive charges the potential is positive and is negative for negative charges.
the formula for electric field is given as-
for positive charges,the line filed is away from it and for negative charges the filed is towards it.
we know that on equitorial line the potential is zero.hence all the points situated on the line passing through centre of the dipole and perpendicular to the dipole length is zero.
here the net electric field due to the dipole can not be zero between the two charges,but we can find the points situated on the axial line but outside of charges where the electric field is zero.
now let the two charges of same nature.let these are positively charged.
here we can not find a point between two charges and on the line joining two charges where the potential is zero.
but at the mid point of the line joining two charges the filed is zero.
Answer:
6.38 x 10^4 J
Explanation:
d = 0.33 cm = 0.33 x 10^-2 m, Area = 87 x 36 cm^2 = 0.87 x 0.36 m^2
ΔT = 14 degree C, t = 1 min = 60 second
K = 0.8 W / m K
Heat = K A ΔT t / d
H = 0.8 x 0.87 x 0.36 x 14 x 60 / (0.33 x 10^-2)
H = 6.38 x 10^4 J
Answer:
I think the answer is
C) iron nails are attracted towards all materials