Radioactive Sr has a half-life of 30 years. What percent of a sample of Sr will remain after 90 years
- 0%
- 75%
- 12.5%
- 50%
The ratio of shortest wavelength to longest of Lyman series is:
- P
- 4
- 3/4
- 4/3
The shortest wavelength associated to Paschen series is:
- λ=8/RH
- λ=4/RH
- λ=9/RH
- λ=19/RH
The wavelength of photon “A” is half the wavelength of photon “B”. The energy of a photon “A” is:
- One-fourth of energy of Photon B
- Equal to energy of Photon B
- Twice the energy of Photon B
- Half the energy of Photon B
For half wave rectification, the number of diode needed in a circuit is:
- 3
- 2
- 4
- 1
For induced emf to be produced in a coil, the magnetic flux linked with a coil must:
- Only decrease
- Only increase
- Be changed
- Be constant
A constant magnetic field of 5T is passing through a static conducting loop of area 0.8 m^2, the induced emf is:
- 4 V
- 32 V
- 10 V
- Zero
When the magnetic force acts on a charge particle, change occurs in:
- Magnitude and direction of velocity
- Magnitude of velocity only
- Neither direction nor magnitude of velocity
- Only the direction of velocity
The magnitude of the magnetic flux through area A has exactly the same value at angles:
- 270° and 360°
- 180° and 270°
- 90° and 180°
- o° and 180°
Ampere second is the unit of:
- Potential difference
- Charge
- Power
- Current
