moseley's law

1.According to moseley, a and b in moseley's law are
A)independent of the material
B)dependent on the material
C)a depends on the material,but b is independent of the material
D)none of these

2.Photoelectric effect supports quantum nature of light because
A)there is a min frequency of light below which no photoelectrons are emitted
B)the max KE of photoelectrons depends only on the frequency of light and not on its intensity
C)even when the metal surface is faintly illuminated,the photoelectrons leave the surface immediately
D)electric charge of photoelectrons is quantised

3.A radioactive material has half life of 1 minute.if one of the nuclei decays now,when will the next one decay.

All questions are from fiitjee rsm.

7 Answers

1
JOHNCENA IS BACK ·

2.A
3.ANYTIME[EACH NUCLEI HAS EQUAL CHANCES AT EVERY INSTANT]

1
Arka Halder ·

Correct answer for 3rd ques,anand.
And 2nd ques is multiple answer.
First is single option correct.
Answer for 2nd one is A,B,C,but i think it should b only A and B.
Plz reply.

1
JOHNCENA IS BACK ·

WELL IF IT IS MCQ...A,B,C ARE CORRECT!!!!!!!![BUT REAL REASON IS ONLY A AS I MENTIONED EARLIER TOO]

1
Arka Halder ·

what about ques 1?

1
pratik anand ·

The answer is (A). a,b depends upon K-series,L-series etc. and not upon any material. For ex. for the lines of K-series a=2.47x1015 and b=1..

11
Tush Watts ·

Ans 1) By Moseley's equation,
√v = a (Z - b )
where v refers to frequency , Z the nuclear charge and, a & b are constants, that depends upon the type of the line.

Ans 2) (a), (b), (c)
The electrons are ejected from the metal surface as soon as the beam of light strikes the surface, i.e., there is no time lag between the striking of light beam and the ejection of electrons from the metal surface.

But I have a dbt in option (d). [2]

1
Arka Halder ·

thnx pratik,tushar.i too think that it wont be D in Q2.

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