Two cells when connected in series are balanced on 8m on a potentiometer. If the cells are connected with polarities of one of the cells is reversed, then they balance on 2m. The ratio of […]
If the series limit of Lyman series for hydrogen atom is equal to the series limit of Balmer series for a hydrogen like atom, then atomic number of this hydrogen like atom is
Options […]
If in a L-R series circuit the power factor is 1/2 and R=100Ω, then the value of L is, when AC mains is used
Options
(a) πH (b) √3/π H (c) π/√3 H (d) […]
The self-inductance of a choke coil is 10 mH. When it is connected with a 10 V DC source, then the loss of power is 20 W. When its is connected with 10 V AC […]
A galvanometer having resistance of 50 Ω requires a current of 100μA to give full scale deflection. How much resistance is required to convert it into an ammeter of range of 10A?
Options
Two thin lenses when placed in contact, then the power of combination is +10 D. If they are kept 0.25 m apart, then the power reduces to +6 D. The focal lengths of the lenses […]
If the focal length of a concave mirror is 50 cm, then where should the object is placed, so that its image is two times and inverted
Options
(a) 55 cm (b) (-75 […]
If a nucleus ᴢXᴬ emits 9α and 5β-particles, then the ratio of total protons and neutrons in the final nucleus is
Options
(a) (Z-13)/(A-36) (b) (Z-13)/(A-Z-13) (c) (Z-18)/(A-36) (d) (Z-13)/(A-Z-23)
Correct Answer:
(Z-13)/(A-Z-23)
In Young’s double slit experiment, the fringe width is 1×10⁻⁴ m, if the distance between the slit and screen is doubled and the distance between two slits is reduced to half and the wavelength is […]
2017 Copyright Doctor Dreams Training Academy