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# The electrical domestic tube light gives white fluorescent light because of

 A) colision between molecules of filled gas under electric current B) heavy current C) vacuum inside the tube D) falling of ultra violet rays on the white inner coating of the tube

Answer:   D) falling of ultra violet rays on the white inner coating of the tube

Explanation:

The ultraviolet rays have high frequency and shorter wavelength are converted to visible white light with lower frequency and greater wave length

Subject: Physics

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• Related Questions

On the Kelvin scale ,the melting point of ice is

 A) 373K B) 100K C) 273K D) 0 K

Explanation:

Subject: Physics

1

Water has maximum density at............

 A) 0 C B) -15 C C) 4 C D) 15 C

Explanation:

Subject: Physics

0

Fish and other aquatic creatures canlive inside a deep frozen pond because

 A) fish are cold-blooded animals B) ice is a bad conductor of heat C) there will always be water just beneath the ice level D) they can adapt themselves to live in ice

Answer & Explanation Answer: C) there will always be water just beneath the ice level

Explanation:

Water has maximum density at $\inline \fn_jvn 4^{0}C$. So at this temperature it sinks down to bottom and stays here. If it cools further, it will become less dense and move up. So while the upper layers can cool enough to form ice, the bottom layers remain as water at $\inline \fn_jvn 4^{0}C$$\inline \fn_jvn \therefore$ (C) is correct.

Subject: Physics

11

At what temperature do the Fahrenheit and celcius scales give the same reading?

 A) 212 degrees B) 32 degreees C) -40 degreees D) 0 degreees

Explanation:

$\inline \fn_jvn F=C\times \frac{9}{5}+32$ We want the temperaature when F=C. So substituting C For F, we have C = $\inline \fn_jvn F=C\times \frac{9}{5}+32$

$\inline \fn_jvn \therefore$ C = -40. Thus when C = -40, we have C = F i.e, $\inline \fn_jvn -40^{0}F$

$\inline \fn_jvn \therefore$ (C) is coorrect. i.e,$\inline \fn_jvn -40^{0}C=-40^{0}F$

Subject: Physics

12

Pieces of camphor placed on water move about rapidly. This is because of

 A) diffusion B) viscosity C) surface tension D) capillarity