Which source emits light that is closest to being truly monochromatic ?
Show answer Hide answer
Answer: C. light form sodium lamp
Explanation
A sodium vapor lamp emits light at very specific, tightly defined wavelengths, making it a standard source of nearly monochromatic light. The electronic transitions in excited sodium atoms produce dominant spectral lines that are exceptionally narrow and pure in color. Unlike broad spectrum thermal sources, sodium discharge lamps minimize polychromatic emissions to provide high spectral purity. Monochromatic light consists of electromagnetic radiation restricted to a single discrete frequency or an extremely narrow spectral band width. Atomic emission spectra depend on quantized electron energy level transitions characteristic of specific chemical elements inside a gas discharge. Sodium D lines are famous yellow spectral features with wavelengths near five hundred eighty-nine nanometers used widely in optics.
Fluorescent tubes rely on phosphor coatings that emit a wide spectrum of blended visible light across multiple wavelengths. Neon lamps produce reddish-orange illumination containing numerous distinct spectral lines rather than a single isolated frequency band. Simple incandescent lamps emit continuous blackbody radiation spanning the entire visible spectrum and beyond into infrared regions.
Related questions
Q1. Mechanical work reaches its maximum value when the angle between force F and displacement vector d equals______________________?
Show answer Hide answer
Answer: D. 0°
Mechanical work formula includes the cosine of the angle between vectors. The cosine of zero degrees evaluates to the maximum value of one. Therefore, parallel force and displacement vectors produce maximum work. Work is...
Q2. What precisely are X-rays________________?
Show answer Hide answer
Answer: C. high energy photons
X-rays are packets of electromagnetic energy classified specifically as high-energy photons. Unlike electrons, photons possess no rest mass and travel at the speed of light. Wilhelm Röntgen discovered these mysterious ra...
Q3. The dimensional formula of work corresponds directly to that of__________________?
Show answer Hide answer
Answer: A. torque
Work is calculated as force multiplied by displacement distance along its line. Torque is calculated as force multiplied by perpendicular lever arm distance. Both physical quantities share the exact same dimensional form...
Q4. In their fundamental nature, X-rays share similarities with_______________?
Show answer Hide answer
Answer: C. γ-rays
X-rays and gamma rays are both forms of high energy electromagnetic radiation. They share identical fundamental wave and particle characteristics in physics. Their primary difference lies in their origin from atomic elec...
Q5. An instrument's zero error is classified as what kind of_________________?
Show answer Hide answer
Answer: C. Systematic error
A zero error is a consistent, reproducible flaw inherent to a measuring instrument's calibration, categorizing it as a systematic error. Because the offset remains constant across repeated trials, it shifts every recorde...
Q6. Which substance exhibits the widest forbidden energy gap ?
Show answer Hide answer
Answer: A. insulator
Insulators possess very wide forbidden energy gaps between valence and conduction bands. Thermal energy at room temperature cannot excite electrons across this wide gap. This absence of free charge carriers prevents elec...