Difference between $name and $name

Question

difference between $name and $name?

Answer 1

its simple....

$name= "hi";
$hi="hey";
echo $name;
using of double "$"
$name it goes to $hi (output hey) 😉

Answer 2

we use $ $twice for variable variable within variable means which its value is declared as other variable.
like $a=5
$b=$a
there is difference when it is compiled

Answer 3

it's nothing but referring value of the another variable