Electricity

• How Much Does a Smartphone Battery’s Mass Increase When Charged?
  A charged smartphone battery is slightly heavier: estimate the change from its stored energy using Δm = ΔE/c², typically well below a nanogram.
• How Does the Water-Flow Analogy Explain Electric Circuits?
  The water-flow analogy links voltage to pressure, current to flow rate, and resistance to pipe restriction, while clarifying where the comparison fails.
• Does Electricity Take the Path of Least Resistance?
  Electricity does not choose only the least-resistance route. Learn how current divides between branches and how circuit laws determine each path.
• What Happens When Different Batteries Are Connected in Parallel?
  Different-voltage batteries in parallel can drive current into each other. Learn how to estimate that current and why mismatched batteries can be unsafe.
• Could Nuclear Bombs Be Used to Generate Electricity?
  A nuclear bomb could release heat that drives a turbine, but turning an explosion into reliable electricity is far less practical than using a controlled reactor.
• Can You Change the Capacitance of a Capacitor?
  You can change a capacitor’s capacitance by changing its plate geometry or dielectric; charge and voltage then respond according to its circuit.
• Can Electrical Resistance Depend on Direction?
  Ordinary linear resistors have the same resistance when current reverses, but anisotropic materials and nonlinear devices can behave differently.