Category: Atomic Spectra

A. Balmer series
B. Pfund series
C. Bracket series
D. Lymann series

A. 10-4 sec
B. 10-5 sec
C. 10-3 sec
D. 10-8 sec

A. The ions in a crystal are well arranged
B. The lines in a diffraction grating cannot reflect X-rays.
C. The penetration power of X-rays is high in a diffraction grating
D. The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal

A. its energy levels are too close to each other
B. its energy levels are too far apart
C. it is too small in size
D. it has a single electron

A. radiate electromagnetic energy with a continuous distribution of wavelength
B. absorb particular wavelengths when white light is incident on them
C. radiate electromagnetic energy of discrete characteristic wavelength
D. emit either invisible or visible light

A. γ-rays
B. Infra red radiation
C. Visible light
D. Ultraviolet rays

A. 10-10s
B. 10-8s
C. 10-6s
D. 10-9s

A. Number of incident electron i.e. filament current
B. The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated
C. The soft target which can easily emit electrons
D. All of above are correct