Answer:
Explanation:
R1 = + 11.7 cm
R2 = - 18.7 cm
n = 1.52
(a) Use lens maker formula



f = 13.84 cm
(b)
R1 = + 18.7 cm
R2 = - 11.7 cm
n = 1.52
(a) Use lens maker formula



f = 13.84 cm
<span>Atoms with the same atomic number but different atomic mass are called:
<span>Isotopes</span>
</span>
(B.) I know it’s not that hard or easy so don’t be made if wrong
(a) 
According to Newton's second law, the force experienced by each balloon is given by:
F = ma
where
m = 0.021 kg is the mass
a = 1.1 m/s^2 is the acceleration
Substituting, we found:

The electrostatic force between the two balloons can be also written as

where
k is the Coulomb's constant
Q is the charge on each balloon
r = 16 m is their separation
Since we know the value of F, we can find Q, the magnitude of the charge on each balloon:

(b)
electrons
The magnitude of the charge of one electron is

While the magnitude of the charge on one balloon is

This charge can be written as

where N is the number of electrons that are responsible for this charge. Solving for N, we find:
