A closed organ pipe and an open organ pipe are tuned to the same fundamental frequency. The ratio of their lengths is
1 : 1
2 : 1
1 : 4
1 : 2
D.
1 : 2
Fundamental frequency of closed pipe,
Fundamental frequency of open pipe,
An observer standing near the sea shore os 54 /min. If the wavelength of the water wave is 10 m then the velocity of water wave is
540 ms-1
5.4 ms-1
0.184 ms-1
9 ms-1
A set of 24 tuning forks are so arranged that each gives 6 beats/s with the previous one. If the frequency of the last tuning fork is double that of the first, frequency of the second tuning fork is
138 Hz
132 Hz
144 Hz
276 Hz
A 10 Ω electric heater operates on a 110 V line. The rate at which heat is developed in watts is
1310 W
670 W
810 W
1210 W
For a certain thermocouple, if the temperature of the cold junction is 0°C, the neutral temperature and inversion temperatures are 285°C and 570°C respectively. If the cold junction is brought to 10°C, then the new neutral and inversion temperatures are respectively
285°C and 560°C
285°C and 570°C
295°C and 560°C
275°C and 560°C
The frequency of X-rays, γ-rays and ultraviolet rays are respectively a, b and c then
a < b, b > c
a > b, b > c
a > b, b < c
a < b, b < c
If c is the speed of electromagnetic waves in vacuum, its speed in a medium of dielectric constant K and relative permeability μr is
The electrostatic field due to a charged conductor just outside the conductor is
zero and parallel to the surface at every point inside the conductor
zero and is normal to the surface at every point inside the conductor
parallel to the surface at every point and zero inside the conductor
normal to the surface at every point and zero inside the conductor
A point charge + q is placed at the midpoint of a cube of side a. The electric flux emerging from the cube is
zero