IIT-JEE-Physics-Screening–2000
SCREENING
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1. Electrons with energy 80keV are incident on the tungsten target of an X-Ray tube. K-shell electrons of tungsten have -72.5keV energy. X-rays emitted by the tube contain only.
(A) a continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of ~0.155 Å.
(B) A continuous X-ray spectrum (Bremsstrahlung) with all wavelengths.
(C) The characteristic X-ray spectrum of tungsten.
(D) A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of ~0.155 Å and the characteristic X-ray spectrum of tungsten.
2. A uniform but time varying magnetic field B (t) exists in a circular region of radius a and is directed into the plane of the paper as shown. The magnitude of the induced electric field at point P at a distance r from the center of the circular region
3. A large open tank has two holes in the wall. One is a square hole of side L at a depth y from the top and the other is a circular hole of radius R at a depth 4y from the top. When the tank is completely filled with water, the quantities of water flowing out per second from both holes are the same. Then, R is equal to
(A) L/√2π
(B) 2πL
(C) L
(D) L/2π
4. An equilateral triangle ABC formed from a uniform wire has two small identical beads initially located at A. The triangle is set rotating about the vertical axis AO. Then the beads are released from rest simultaneously and allowed to slide down; One along AB and the other along AC as shown. Neglecting frictional effects, the quantities that are conserved as beads slides down are
5. A cubical block of side L rests on a rough horizontal surface with coefficient of friction μ. A horizontal force F is applied on the block as shown. If the coefficient of friction is sufficiently high so that the block does not slide before toppling, the minimum force required to topple the block is
(A) Infinitesimal
(B) mg/4
(C) mg/2
(D) mg(1-μ)
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