Verified Solution • 2025–26 Session moderate

QPages 352-354: Q5: HC Verma: Concepts of Physics - Volume 2 Electric Current through Gases Pages 352-354: Q5 Solution: Calculate for tungsten emitter at , and , where represents the…

Calculate nT)/n1000 K)nT)/n1000 \text{ K}) for tungsten emitter at T=300 KT = 300 \text{ K}, 2000 K2000 \text{ K} and 3000 K3000 \text{ K}, where nT)nT) represents the number of thermions emitted per second by the surface at temperature T. Work function of tungsten is 4.52 eV.

Step-by-Step Verified Solution

**Answer:** (a) 7.05×10−557.05 \times 10^{-55} (b) 8.5×10−118.5 \times 10^{-11} (c) 1.3×10−31.3 \times 10^{-3}. **Step-by-Step Explanation:** Using Richardson-Dushman equation: n(T)∝T2e−ϕ/kTn(T) \propto T^2 e^{-\phi/kT} where ϕ=4.52\phi = 4.52 eV. n(1000)∝(1000)2e−4.52×1.6×10−19/(1.38×10−23×1000)=106×e−52.4=1.74×10−17n(1000) \propto (1000)^2 e^{-4.52 \times 1.6 \times 10^{-19}/(1.38 \times 10^{-23} \times 1000)} = 10^6 \times e^{-52.4} = 1.74 \times 10^{-17}. (a) T=300T = 300 K: n(T)/n(1000)=(300/1000)2e−52.4(1000/300−1)≈7.05×10−55n(T)/n(1000) = (300/1000)^2 e^{-52.4(1000/300 - 1)} \approx 7.05 \times 10^{-55}. (b) T=2000T = 2000 K: ratio ≈8.5×10−11\approx 8.5 \times 10^{-11}. (c) T=3000T = 3000 K: ratio ≈1.3×10−3\approx 1.3 \times 10^{-3} .

All Questions in this Chapter

QPage 351: Q1 QPage 351: Q2 QPage 351: Q3 QPage 351: Q4 QPage 351: Q5 QPage 351: Q6 QPage 351: Q7 QPage 351: Q8 QPage 351: Q9 QPage 351: Q10 QPage 352: Q1 QPage 352: Q2 QPage 352: Q3 QPage 352: Q4 QPage 352: Q5 QPage 352: Q6 QPage 352: Q7 QPages 351-352: Q1 QPages 351-352: Q2 QPages 351-352: Q3 QPages 351-352: Q4 QPages 351-352: Q5 QPages 351-352: Q6 QPages 351-352: Q7 QPages 351-352: Q8 QPages 351-352: Q9 QPages 352-354: Q1 QPages 352-354: Q2 QPages 352-354: Q3 QPages 352-354: Q4 QPages 352-354: Q5 QPages 352-354: Q6 QPages 352-354: Q7 QPages 352-354: Q8 QPages 352-354: Q9 QPages 352-354: Q10 QPages 352-354: Q11 QPages 352-354: Q12 QPages 352-354: Q13 QPages 352-354: Q14 QPages 352-354: Q15 QPages 352-354: Q16 QPages 352-354: Q17 QPages 352-354: Q18 QPages 352-354: Q19 QPages 352-354: Q20 QPages 352-354: Q21 QPages 352-354: Q22 QPages 352-354: Q23

Related Learning Resources & Exam Preparation

Chapter Practice Bank
Practice all topic-wise questions from Electric Current through Gases
Reference Textbook Solutions
Explore complete chapter exercises for HC Verma: Concepts of Physics - Volume 2
Competitive PYQ Question Bank
Browse year-wise authentic previous years' questions with solutions
Authentic CBT Mock Tests
Simulate official exam environment with live timer and percentile scoring