Answer:
It was most likely static electricity
Explanation:
Static electricity comes down to the interactive force between electrical charges.
So because your computer charger has electricity the foil is a conductor so the sparks were most likely static electricity
Explanation:
Bases taste bitter, feel slippery, and conduct electricity when dissolved in water. Indicator compounds such as litmus can be used to detect bases. Bases turn red litmus paper blue. The strength of bases is measured on the pH scale.
Answer:

Explanation:
given,
refractive index of lens, n = 1.70
Radius of curvature of front surface. R₁ = 20 cm
Radius of curvature of the back surface, R₂ = 30 cm
focal length= ?

R₁ = +20 cm
R₂ = -30 cm
n = 1.70




the focal length of the lens is equal to 17.15 cm