HelpContactFor teachers and institutes
>_StemPy Lab
Mock TestsClassesGroups

>_StemPy Lab

Learn. Solve. Code the solutions. Test yourself.

Live examsFree mock exams, timed and rankedEveryone starts together, and your score and rank come the moment it ends.See the exams →

Learn

  • Physics
  • Chemistry
  • Mathematics
  • Biology
  • Python Programming
  • Statistics & Data Science
  • Classes
  • Groups

Practice

  • Problems
  • Quizzes
  • Mock Tests
  • Question Sets
  • Exams
  • Certificates
  • Python Labs
  • AI Practice Generator
  • Student-Created Tests

Community

  • Discussions
  • Resources
  • Notes
  • Blog

Account

  • Dashboard
  • My Content
  • Profile
  • Log in
© 2026 senLearn. All rights reserved.HelpAboutContactPrivacy PolicyTerms of UseRefund Policy
  1. Problems
  2. /Modern Physics

Modern Physics

Physics

Relativity and mass-energy equivalence.

+ Upload a Problem
Subtopic
8 problems
Type:
1.
Hydrogen atoms are excited to the level n = 3.
High School (11–12) · Atoms and Atomic SpectraStemPy LabStemPy Lab
Medium
2.
A metal surface has a work function of 2.4 eV.
High School (11–12) · Dual Nature of Radiation and MatterStemPy LabStemPy Lab
Medium
3.
The Lyman series is every jump that ends on n = 1.
High School (11–12) · Atoms and Atomic SpectraArnieArnie
Hard
4.
How much energy ionises (a) a hydrogen atom whose electron is in the level n = 5, and (b) a He⁺ ion…
High School (11–12) · Atoms and Atomic SpectraArnieArnie
Easy
5.
Find the energy of hydrogen's electron in the level n = 3.
High School (11–12) · Atoms and Atomic SpectraArnieArnie
Easy
6.
Two beams have the same frequency, and one is much brighter.
High School (11–12) · Dual Nature of Radiation and MatterArnieArnie
Medium
7.
The stopping voltage is 0.45 V for light of 6.0 × 10¹⁴ Hz, and 1.68 V for 9.0 × 10¹⁴ Hz.
High School (11–12) · Dual Nature of Radiation and MatterArnieArnie
Medium
8.
A metal has a work function of 2.75 eV. Ultraviolet light of 350 nm falls on it.
High School (11–12) · Dual Nature of Radiation and MatterArnieArnie
Easy