A certain X-ray tube requires a current of 5 mA at a voltage of 60kV. The rate of energy dissipation (in watts) is:
- 200
- 560
- 300
- 800
Of the following, the copper conductor that has the least resistance must be:
- Thin, long and hot
- Thin, short, cool
- Thick, short and cool
- Thick, long, hot
In how many hours a 1000 watt AC will consume one unit of electricity
- 0.5 hr
- 1.5 hr
- 2 hr
- 1 hr
A wire of length L has resistivity ρ. If the wire is divided in two halves, then resistivity of each halve is:
- ρ
- ρ/3
- ρ/2
- 2p
1 volt × 1 ampere is equal to:
- 1 coulomb
- 1 hp
- 1 watt
- 1 newton
For 0.5 Siemens of conductance, resistance will be:
- 1Ω
- 20 Ω
- 10 Ω
- 2Ω
Work done during isochoric process is:
- Negative
- Maximum Positive
- Maximum Negative
- Zero
The expression Cp – R is equal to:
- R
- R + Cv
- Cv
- Cp – Cv
If the pressure of air enclosed in a long tube Is increased 10 times, then speed of sound will:
- Remain constant
- Become zero
- Decrease
- Increase
The square root of the ratio of elasticity to mass density is equal to:
- Product of frequency and wavelength
- Refractive index
- Co-efficient of Viscosity
- Force
