Please select a subject first
Advertisements
Advertisements
Answer the following question.
An optical instrument uses a lens of 100 D for the objective lens and 50 D for its eyepiece. When the tube length is kept at 20 cm, the final image is formed at infinity.
(a) Identify the optical instrument.
(b) Calculate the magnification produced by the instrument.
Concept: undefined >> undefined
Sodium and copper have work function 2.3 eV and 4.5 eV respectively. Then, the ratio of the wavelengths is nearest to ______.
Concept: undefined >> undefined
Advertisements
The electric flux through the surface ______.
 |
 |
 |
 |
| (i) | (ii) | (iii) | (iv) |
Concept: undefined >> undefined
Concept: undefined >> undefined
Concept: undefined >> undefined
Concept: undefined >> undefined
Concept: undefined >> undefined
A charged particle q is placed at the centre O of cube of length L (A B C D E F G H). Another same charge q is placed at a distance L from O. Then the electric flux through ABCD is ______.
Concept: undefined >> undefined
- In an external electric field, the positive and negative charges of a non–polar molecule are displaced in opposite directions.
- In non –polar molecules displacement stops when the external force on the constituent charges of the molecule is balanced by the restoring force.
- The non–polar molecule develops an induced dipole moment.
Concept: undefined >> undefined
Two cells of emfs approximately 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm.
Concept: undefined >> undefined
Concept: undefined >> undefined
Concept: undefined >> undefined
Concept: undefined >> undefined
A coil of circular cross-section having 1000 turns and 4 cm2 face area is placed with its axis parallel to a magnetic field which decreases by 10–2 Wb m–2 in 0.01 s. The e.m.f. induced in the coil is ______.
Concept: undefined >> undefined
A metallic rod of mass per unit length 0.5 kg m–1 is lying horizontally on a smooth inclined plane which makes an angle of 30°with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is ______.
Concept: undefined >> undefined
A charged particle enters in a uniform magnetic field with a certain velocity. The power delivered to the particle by the magnetic field depends on ______.
Concept: undefined >> undefined
A current carrying circular loop of radius R is placed in the x-y plane with centre at the origin. Half of the loop with x > 0 is now bent so that it now lies in the y-z plane.
Concept: undefined >> undefined
A proton and an alpha particle both enter a region of uniform magnetic field B, moving at right angles to field B. If the radius of circular orbits for both the particles is equal and the kinetic energy acquired by proton is 1 MeV the energy acquired by the alpha particle will be ______.
Concept: undefined >> undefined
Concept: undefined >> undefined
Concept: undefined >> undefined
