Explanation:
It is given that,
Mass of platinum bar, m = 750 g
Length of the bar, l = 5 cm
Breadth of the bar, b = 4 cm
Width of the bar, h = 1.5 cm
Volume of the bar, 

We need to find the density of the platinum bar. The density of any substance is given by :



So, the density of the platinum bar
. Hence, this is the required solution.
Answer:
An unknown number of identical light bulbs are connected to a 15 V battery in parallel. The current through the battery is 2 A. If the light bulbs are connected to the battery in series, the current through the battery is 5 mA. How many bulbs are there?
3 bulbs are there from the analogy given above
Explanation:
-- pass the light through a lens
The path of the light is bent (refracted) to a new direction.
-- bounce the light off a shiny surface
The light is sent back (reflected) in the direction from which it arrived.
-- pass the light through a prism
The light is spread out according to the different wavelengths
that may be in it.
-- put something black in the light's path
The light is completely absorbed and is never seen again.
-- turn the light off
The source stops emitting light.
-- throw a towel over the lamp
The light is absorbed in the towel, and not seen outside of it.
Answer:
In particle physics, a lepton is an elementary particle of half-integer spin (spin 1⁄2) that does not undergo strong interactions.[1] Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutral leptons (better known as neutrinos). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium, while neutrinos rarely interact with anything, and are consequently rarely observed. The best known of all leptons is the electron.