33% OFF
JEE Main Ultimate Online Test Series - 2027
331 Topic Tests87 Chapter Tests30 Full Tests10 Part Tests
- Most Relevant Questions for JEE Main 2027
- JEE Main Predictive Percentile and Rank
- Best Solution to Every Question
- Very Detailed Analysis
₹999 ₹1,499
Save ₹500
Access valid till 31 May 2027
1
JEE Main 2020 (Online) 7th January Morning Slot
Numerical
+4
-0
A beam of electromagnetic radiation of intensity 6.4 × 10–5 W/cm2 is comprised of wavelength,
$$\lambda $$ = 310 nm. It falls normally on a metal (work function $$\phi $$ = 2eV) of surface area of 1 cm2. If one
in 103 photons ejects an elctron, total number of electrons ejected in 1 s is 10x. (hc = 1240 eVnm,
1eV = 1.6 × 10–19 J), then x is _____.
Your input ____
JEE Main Subjects
Browse all chapters by subject
Physics
Mechanics
Units & Measurements Vector Algebra Motion in a Straight Line Motion in a Plane Circular Motion Laws of Motion Work Power & Energy Center of Mass and Collision Rotational Motion Properties of Matter Heat and Thermodynamics Simple Harmonic Motion Waves Gravitation
Electricity
Electrostatics Current Electricity Capacitor Magnetic Effect of Current Magnetic Properties of Matter Electromagnetic Induction Alternating Current Electromagnetic Waves
Optics
Modern Physics
Chemistry
Physical Chemistry
Some Basic Concepts of Chemistry Structure of Atom Redox Reactions Gaseous State Chemical Equilibrium Ionic Equilibrium Solutions Thermodynamics Electrochemistry Chemical Kinetics and Nuclear Chemistry Solid State Surface Chemistry
Inorganic Chemistry
Periodic Table & Periodicity Chemical Bonding & Molecular Structure Isolation of Elements Hydrogen s-Block Elements p-Block Elements d and f Block Elements Coordination Compounds Salt Analysis Environmental Chemistry
Organic Chemistry
Mathematics
Algebra
Sets and Relations Logarithm Quadratic Equation and Inequalities Sequences and Series Mathematical Induction Binomial Theorem Matrices and Determinants Permutations and Combinations Probability Vector Algebra 3D Geometry Complex Numbers Statistics Mathematical Reasoning
Trigonometry
Trigonometric Ratio and Identites Trigonometric Equations Inverse Trigonometric Functions Properties of Triangle Height and Distance
Coordinate Geometry
Calculus