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PHOTOELECTRIC EFFECT NUMERICALS _ NCERT CLASS 12 SOLUTIONS _CHAPTER 11

 PHOTOELECTRIC EFFECT NUMERICALS _ NCERT CLASS 12 SOLUTIONS _CHAPTER 11

 




11.6 In an experiment on photoelectric effect, the slope of the cut-off voltage versus frequency of incident light is found to be 4.12 × 10^–15 V s. Calculate the value of Planck’s constant. 
 
 11.8 The threshold frequency for a certain metal is 3.3 × 10^14 Hz. If light of frequency 8.2 × 10^14 Hz is incident on the metal, predict the cutoff voltage for the photoelectric emission. 
 
 11.9 The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelength 330 nm? 11.10 Light of frequency 7.21 × 10^14 Hz is incident on a metal surface. Electrons with a maximum speed of 6.0 × 10^5 m/s are ejected from the surface. What is the threshold frequency for photoemission of electrons? 
 
 11.11 Light of wavelength 488 nm is produced by an argon laser which is used in the photoelectric effect. When light from this spectral line is incident on the emitter, the stopping (cut-off) potential of photoelectrons is 0.38 V. Find the work function of the material from which the emitter is made.

CLASS 7 PERCENTAGE OLYMPIAD WORKSHEET WITH SOLUTIONS - MATHS

 CLASS 7 PERCENTAGE OLYMPIAD WORKSHEET WITH SOLUTIONS - MATHS






OLYMPIAD PRACTICE - WITH SOLUTIONS
 
A boy has enough money to buy 20 books. If each book costs 25 paise less, he could buy two more books and still have 70 paise left. How much money does the boy have? (A) Z 16 (B) Z 24 (C) Z 48 (D) Z 36 
 
When a number is reduced by 4, it becomes 80% of itself. Find the number. (A) 20 (B) 30 (C) 40 (D) 50 1 
 
If 2 1/2 % of a number is 0.2, what will be 120% of it? (A) 10.8 (B) 4.8 (C) 9.6 (D) 12.4 
 
The number of seats for admission is increased by 10% every year. If the number of seats in 2001 was 400, what was the number of seats in 2003? (A) 824 (B) 484 (C) 500 (D) 480