JJ Thomson proved John Dalton's theory wrong, as Thomson discovered the electron. This showed that there were particles that were smaller than an atom, despite Dalton claiming that the atom is the smallest unit of matter.
C.
This is basically the definition of percent composition which is how much mass a element contributes to a specific molecule.
Answer:- C. Hafnium.
Solution:- Mass of the sample is 46.0 g and it's volume is
.
From mass and volume, we can calculate it's density using the formula:



On the basis of the density, this substance could either be mercury or hafnium. Since the substance is a solid at room temperature where as mercury is liquid. So, it can't be mercury.
The right choice is C) Hafnium.
Answer:
R = 40 ohms
Explanation:
Given that,
The voltage of outlet, V = 120 V
Current flowing through the device, I = 3 A
We need to find the Resistance rating of the power cord. Let the resistance is R. We know that,
Ohm's law, V = IR
Put all the values,

So, the resistance rating of the power cord is equal to 40 ohms.