Explanation

• Water has its minimum density at 0°C.
• Water has its maximum density at 4°C.

Explanation

Sputnik 1 was the first artificial Earth satellite.

It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program.

ND2-03-2023

Explanation

One up quark and two down quarks, when combined, make a neutron. 

More specifically:

A proton consists of two up quarks and one down quark (uud). 

A neutron consists of one up quark and two down quarks (udd). 

An electron and a positron are elementary particles, not composed of quarks. 

Explanation

For an ideal gas, a graph of pressure (P) versus volume (V) at a constant temperature gives a hyperbolic curve, as described by Boyle's Law (PV = k).

This indicates an inverse relationship: as pressure increases, volume decreases, and vice versa.

However, if the graph is plotted between pressure (P) and the inverse of volume (1/V), it will be a straight line with a positive slope, passing through the origin

Explanation

The radius of an atomic orbital increases with the square of the principal quantum number (n).
So, larger values of n result in electrons being farther from the nucleus:

Radius∝n2

Explanation

In an optical fiber, the core is made of a material with a relatively high refractive index, typically glass or plastic with a high refractive index.

This allows the light to be confined and transmitted through the fiber via total internal reflection.

The cladding surrounding the core has a lower refractive index, which helps to keep the light within the core.

Explanation

The first scientist who gave the concept of gravitation was Sir Isaac Newton.

He published his groundbreaking work, "Universal Law of Gravitation," in 1687.

It explained how gravity works and how it affects objects on Earth and in the universe.

Explanation

A tightrope walker carries a long pole to lower their center of gravity, making it easier to balance and maintain equilibrium.

By spreading their weight over a larger area (including the pole), they reduce the risk of toppling over.

Explanation

• RKA (Roscosmos) is the space agency of Russia.
• It was established in 1992.
• RKA is the Russian Federal Space Agency, formerly the Soviet Space Program, which launched Sputnik 1, the first artificial satellite, and sent Yuri Gagarin, the first human, to space.
• Roscosmos is headquartered in Moscow.

Explanation

To obtain greater dispersion by a diffraction grating, the slit separation should be decreased. 

Dispersion:

• In diffraction gratings, dispersion is the separation of light wavelengths during diffraction, with greater dispersion resulting in wider color separation.

Slit separation:

• The distance between individual slits on the grating is called the slit separation.

Relationship between slit separation and dispersion:

• Smaller slit separations lead to larger angles of diffraction for a given wavelength, resulting in greater dispersion.
• Imagine the light waves as being "bent" more by the closer slits, causing them to spread out further