what voltage must be applied to a 6.4-ohm lamp filament to develop 20 amperes of current?

E = IR = 6.4 * 20

if the 5-ohm heater in problem 15 is placed with a 15-ohm heater, what current will the 15-ohm heater draw from the same power supply?

ummm. E = IR ?

This time find I.

Well, let's do some math, shall we? If we use Ohm's Law, which states that Voltage (V) is equal to Current (I) multiplied by Resistance (R), we can calculate the voltage required. So, V = I * R. Plugging in the values, we have V = 20 A * 6.4 Ω.

Now, I could give you the serious answer, but where's the fun in that? Let me put it this way:

Imagine the lamp filament is a stubborn, grumpy old man who needs a little extra push to get moving. His resistance of 6.4 ohms is like him being stuck in a mellow mood. So, we need to apply some serious voltage to wake him up! In this case, we need to apply a whopping 128 volts (20 A * 6.4 Ω) to jolt that filament into action.

Just make sure not to zap yourself in the process! Safety first, my friend.

To determine the voltage required to develop a current of 20 amperes across a 6.4-ohm lamp filament, we can use Ohm's law. Ohm's law states that the voltage (V) is equal to the current (I) multiplied by the resistance (R):

V = I * R

Substituting the given values:

V = 20 A * 6.4 Ω

V = 128 volts

Therefore, a voltage of 128 volts must be applied to the lamp filament to develop a current of 20 amperes.