List of top Questions asked in Bihar Combined Entrance Competitive Examination- 2017

The minimum number of geostationary satellites required for uninterrupted global coverage is

The reason a moving coil galvanometer cannot be used with an alternating current is that

An electron and a proton enter a magnetic field perpendicularly both have same kinetic energy. Which of the following is true?

Select the output Y of the combination of gates shown in figure for inputs A = 1, B = 0; A = 1, B = 1 and A = 0, B = 0 respectively.

If the vertical component of earth's magnetic field at a place is √3 times the horizontal component, then the value of dip at that place is

The temperature co-efficient of resistance of a wire is 0.00125/°C. Its resistance is 1Ω at 300 K. At what temperature, its resistance will be 2Ω?

Two thin lenses have a combined power of +9D. When they are separated by a PY distance of 20 cm, their equivalent power becomes \(+\frac{27}{5}D\), then their individual powers are

If the mass shown in figure is slightly displaced and then let go, then the system shall oscillate with a time period of

If θ is the polarising angle for two optical media whose critical angles are C₁ and C₂ then the correct relation is

In Young's double slit experiment, using a monochromatic light of wavelength λ, the intensity of light at a point on the screen where path difference is \(\lambda\) is K units. Then the intensity of light at a point where path difference is \(\frac{\lambda}{3}\) is

A 1 cm height needle is placed at a distance of 0.1 m from a convex mirror of focal length 0.05 m, then size of the image is

A transformer of efficiency 90% has turns ratio 1: 10. If the voltage across the primary is 220 V and current in the primary is 0.5 A, then the current in secondary is

The relative permeability is represented by μ_r and the susceptibility by X for a magnetic substance. Then for a paramagnetic substance

Two long parallel wires placed 0.08 m apart carry currents 3 A and 5 A in the same direction. What is the distance from the conductor carrying larger current to the point where the resultant magnetic field is zero ?

A copper wire of 3 mm² cross sectional area carries a current of 5 ampere. The magnitude of the drift velocity for the electrons in the wire, (Assume copper to be monovalent, M_cu 63.5 kg/k mol and density of copper = 8920 kg/m³)

A stream of water flowing horizontally with a speed of 15 ms^-1 gushes out of a tube of cross-sectional area 10^-2m² and hits a vertical wall nearly. The force exerted on the wall by the impact of water assuming it does not rebound is

In the circuit below, the potential difference between A and B is

An electric field \(\vec{E}=(2\hat{i}+3\hat{j})N/C\) exists in space. The potential difference (V_P - V_Q) between two points P and Q whose position vectors \(\vec{r}_P=\hat{i}+2\hat{j}\) and \(\vec{r}_Q=2\hat{i}+\hat{j}+\hat{k}\) is

Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 30° with each other. When suspended in a liquid of density 0.8 g cm^-3 the angle remains the same. If density of the material of the sphere is 1.6 g cm^-3, the dielectric constant of the liquid is

In the circuit of figure, treat diode as ideal, current in the 4Ω resistor is

A stationary object is released from a point P a distance 3R from the centre of the moon which has radius R and mass M. Which one of the following expressions gives the speed of the object on hitting the moon ?

A travelling microscope is focussed on an jnk dot. When a glass slab (n = 1.5) of thickness 9 cm is introduced on the dot, the travelling microscope has to be moved by

The half life period of a radioactive element X is same as the mean life time of another radioactive element Y. Initially they have the same number of atoms. Then

In Balmer series for hydrogen atom, find the energy of photon corresponding to longest wavelength.

Cobalt-57 is radioactive, emitting β-particles. The half life for this is 270 days. If 100 mg of this is kept in an ' open container the mass of Cobalt - 57 after 540 days will be