Explanation

The SI unit of electric resistance is the ohm (Ω).

1 Ω = 1 V/A.

while

The SI unit of resistivity is an ohm-meter.

Explanation

In passive voice, "Please" changes to a polite request: You are requested.

The tense remains present, so "are requested" is correct.

Explanation

Red light rays have the lowest frequency and highest wavelength value.

Blue or violet light has the shortest wavelength.

Explanation

Refraction is the bending of light as it passes from one medium to another (e.g., air to water).

This occurs due to a change in the speed of light in different media.

Explanation

Zealous mean پرجوش 

Nonchalant پرسکون describes someone relaxed, calm 

Lazy سست describes someone unwilling to work or use energy

Explanation

The SI unit of pressure is Pascal (represented as Pa) 

in SI base units, one kilogram per meter per second squared (N/m2 or kg m-1s-2)

Definition of Pressure: Pressure can be defined as the force acting per unit area.

***

The SI unit of energy/work is the joule (J)

ND23-9-2023

Explanation

1. The frequency ($f$) of a wave is inversely proportional to its wavelength ($\lambda$) when the wave speed ($v$) is constant.

2. The fundamental wave equation is:

   $$\mathrm{<font\; color="\#0000ff"><b>v</b></font>}<font\; color="\#0000ff"><b>=</b></font>\mathrm{<font\; color="\#0000ff"><b>f</b></font>}\mathrm{<font\; color="\#0000ff"><b>\lambda </b></font>}$$

   where:

   • $v$ = wave speed (m/s),

   • $f$ = frequency (Hz),

   • $\lambda$ = wavelength (m).

3. This applies to all types of waves (e.g., sound, light).

Explanation

Vertical columns in the periodic table are called groups.

Horizontal rows are called periods.

Explanation

1 meter (m) = 1000 millimeters (mm)

1 meter (m) = 100 centimeters (cm)

1 centimeter (cm) = 10 millimeters (mm)

1 millimeter (mm) = 0.1 centimeters (cm)

1 kilometer (km) = 1000 meters (m)

Explanation

A spectrometer is an instrument used to measure the properties of light over a specific portion of the electromagnetic spectrum, especially to analyze line spectra produced by atoms or molecules.

It helps identify elements or compounds by detecting their unique emission or absorption lines in the spectrum.

A spectrometer is an instrument used to measure the wavelength of light (or other electromagnetic radiation) by dispersing it into a spectrum.

It is commonly used to analyze the spectral lines of elements, which correspond to specific wavelengths.