1. Xtra Edge February 2012 - Career Point
1. Xtra Edge February 2012 - Career Point 1. Xtra Edge February 2012 - Career Point
1. A particle of charge Q and of negligible initial speed is accelerated through a potential difference of U. The particle reaches a region of uniform magnetic field of induction B, where it undergoes circular motion. If potential difference is doubled & B is also doubled then magnetic moment of the circular current due to circular motion of charge Q will become (A) double (B) half (C) four times (D) remain same 2. Three long rod AA, AB, CC are moving with a speed v in a uniform magnetic field B perpendicular to the plane of paper as shown in figure. The triangle formed between the three wires is always an equilateral triangle. If resistance per unit length of wire is λ , then the induced current in the triangle is A B × × × × × × × B0 × × × × × × × v v × × × × × × × × × × × × × × C B × × × × × C A (A) v 3λ (C) v 3λ Physics Challenging Problems This section is designed to give IIT JEE aspirants a thorough grinding & exposure to variety of possible twists and turns of problems in physics, that would be very helpful in facing IIT JEE. Each and every problem is well thought of in order to strengthen the concepts and we hope that this section would prove a rich resource for practicing challenging problems and enhancing the preparation level of IIT JEE aspirants. By : Dev Sharma Solutions will be published in next issue Director Academics, Jodhpur Branch v B0 B0 2B0 (B) λ 3 v B0 B0 (D) λ 3. In the diagram shown, the wires P1Q1 and P2Q2 are made to slide on the rails with same speed of 5m/s. In this region a magnetic field of 1T exists. The electric current in 9 Ω resistor is × × P1 × × P2 × × × × × × × × × × × × × 4cm × 2Ω × × × 2Ω × × × × × 9Ω × × × × × × × × × × × × × × × × × × Q1 Q2 v (A) zero if both wires slide towards left (B) zero if both wires slide in opposite direction (C) 0.2mA if both wires move towards left (D) 0.2mA if both wires move in opposite direction 4. A circular current loop is shown in the adjacent figure. The magnetic field in the region is along xaxis and its magnitude in the space is increasing with increasing y-coordinate. The net magnetic force on the loop is XtraEdge for IIT-JEE 14 FEBRUARY 2012 y (A) along + z-axis (B) along –z-axis (C) along +y-axis (D) None of these 5. A point charge q moves from A to B along a parabolic path (AB is latus rectum). Electric field is along x-axis. The work done by the field is y B y 2 A B = 4ax (A) – qEa (B) –2qEa (C) +qeA (D) 2qEa 6. In a cylindrical zone of radius R, magnetic field → B is present perpendicular to the plane of the paper into it. Magnitude of → B is varying with time as B0(p + qt) where p & q are positive constant. Consider a static triangle loop OAM. Emf induced in the triangular loop x x E Set # 10
(A) (C) A 2B0πqR 3 B 0 PR 3 2 × × × × O B × × R × × 60º 60º × × × × × × × × × × × × × × 2 (B) B 0 M qR 3 2 PB R (D) 2 2 0 7. Consider cylindrical region of the magnetic field shown in the figure. Region I and II have fields directed perpendicularly outward and inward respectively. Fields are varying with time as Region I : B = 3B0t Region II : B = B0t There is no net induced electric field in the region 2 ⎛ r ⎞ outside the magnetic field then the ratio of ⎜ 2 ⎟ = ⎝ r1 ⎠ Region I × × × × × × × × r2 × × r1 × × × × × × Region II 8. Match the column: Column – I Column – II (A) In a series RLC circuit if C decreases (P) Z may increase (B) In a series RLC circuit if L increases (Q) Z may decrease (C) In a series RLC (R) resonance circuit if R decreases frequency increases (D) In a series RLC (S) power factor circuit if C increases decrease • After travelling 2.4 billion miles in just over 6 years to reach Jupiter, Galileo missed its target at the Jovian moon Io by only 67 miles. That's like shooting an arrow from Los Angeles at a bull's-eye in New York and missing by only 6 inches! • Utopia ia a large, smooth lying area of Mars. • The biggest star has a diameter of 1800 million miles, making it 2000 times bigger than the Sun. • 15% of the world's fresh water flows doen the Amazon. • In 1995, each American used an annual average of 731 pounds of paper, more than double the amount used in the 1980's. Contrary to predictions that computers would displace paper, consumption is growing. • The term 'black hole' was coined in 1968 when John Wheeler described how an in-falling object 'becomes dimmer millisecond by millisecond...light and particles incident from outside...go down the black hole only to add to its mass and increase its gravitational attraction.' • The 'Red Planet' isn't really red at all, Nasa photographs indicate that it is more of a tan or butterscotch colour. • The International Space Station orbits at 248 miles above the Earth. • The axis of orbit of the planet Uranus is tilted at a 90 degree angle. • Astronomers have discovered over 10,000 asteroids - but put them together and they would be smaller than the Moon. • Have you ever seen a ring around the moon? Folklore has it that this means bad weather is coming. XtraEdge for IIT-JEE 15 FEBRUARY 2012
- Page 3 and 4: Volume - 7 Issue - 8 February, 2012
- Page 5 and 6: 25% increase in number of girls fro
- Page 7 and 8: Dr Amitabha Ghosh was the only Asia
- Page 9 and 10: Sol. (i) The capacitor A with diele
- Page 11 and 12: Sol. (i) Let m be the mass of elect
- Page 13 and 14: Step 5. 1 gram equivalent acid neut
- Page 15: = 2π ∫ π 2 / 3 2 t sec dt 2 t 1
- Page 19 and 20: PHYSICS 1. AB and CD are two ideal
- Page 21 and 22: 4. In a Young's experiment, the upp
- Page 23 and 24: Matter Waves : Planck's quantum the
- Page 25 and 26: The intercept of V0 versus ν graph
- Page 27 and 28: PHYSICS FUNDAMENTAL FOR IIT-JEE The
- Page 29 and 30: etween total mass and number of mol
- Page 31 and 32: KEY CONCEPT Organic Chemistry Funda
- Page 33 and 34: KEY CONCEPT Inorganic Chemistry Fun
- Page 35 and 36: 1. It is possible to supercool wate
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- Page 39 and 40: MATHEMATICAL CHALLENGES 1. as φ (a
- Page 41 and 42: 9. Point P (x, 1/2) under the given
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- Page 45 and 46: dx (ii) ∫ 2 ax + bx + c This can
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- Page 61 and 62: 21. Column-I Column-II (A) If y = 2
- Page 63 and 64: (A) potential energy (PE) increases
- Page 65 and 66: 2. In the reaction 3 Cu + 8 HNO3
(A)<br />
(C)<br />
A<br />
2B0πqR<br />
3<br />
B<br />
0<br />
PR<br />
3<br />
2<br />
× ×<br />
×<br />
×<br />
O B ×<br />
×<br />
R<br />
×<br />
×<br />
60º 60º<br />
×<br />
×<br />
×<br />
×<br />
× × ×<br />
× × ×<br />
× ×<br />
× ×<br />
2<br />
(B)<br />
B<br />
0<br />
M<br />
qR<br />
3<br />
2<br />
PB R<br />
(D)<br />
2<br />
2<br />
0<br />
7. Consider cylindrical region of the magnetic field<br />
shown in the figure. Region I and II have fields<br />
directed perpendicularly outward and inward<br />
respectively. Fields are varying with time as<br />
Region I : B = 3B0t<br />
Region II : B = B0t<br />
There is no net induced electric field in the region<br />
2<br />
⎛ r ⎞<br />
outside the magnetic field then the ratio of<br />
⎜ 2<br />
⎟ =<br />
⎝ r1<br />
⎠<br />
Region I<br />
×<br />
×<br />
×<br />
×<br />
×<br />
×<br />
× ×<br />
r2 ×<br />
×<br />
r1<br />
×<br />
×<br />
×<br />
× × ×<br />
Region II<br />
8. Match the column:<br />
Column – I Column – II<br />
(A) In a series RLC<br />
circuit if C decreases<br />
(P) Z may increase<br />
(B) In a series RLC<br />
circuit if L increases<br />
(Q) Z may decrease<br />
(C) In a series RLC (R) resonance<br />
circuit if R decreases frequency increases<br />
(D) In a series RLC (S) power factor<br />
circuit if C increases decrease<br />
• After travelling 2.4 billion miles in just over 6<br />
years to reach Jupiter, Galileo missed its target at<br />
the Jovian moon Io by only 67 miles. That's like<br />
shooting an arrow from Los Angeles at a<br />
bull's-eye in New York and missing by only 6<br />
inches!<br />
• Utopia ia a large, smooth lying area of Mars.<br />
• The biggest star has a diameter of 1800 million<br />
miles, making it 2000 times bigger than the Sun.<br />
• 15% of the world's fresh water flows doen the<br />
Amazon.<br />
• In 1995, each American used an annual average<br />
of 731 pounds of paper, more than double the<br />
amount used in the 1980's. Contrary to<br />
predictions that computers would displace paper,<br />
consumption is growing.<br />
• The term 'black hole' was coined in 1968 when<br />
John Wheeler described how an in-falling object<br />
'becomes dimmer millisecond by<br />
millisecond...light and particles incident from<br />
outside...go down the black hole only to add to<br />
its mass and increase its gravitational attraction.'<br />
• The 'Red Planet' isn't really red at all, Nasa<br />
photographs indicate that it is more of a tan or<br />
butterscotch colour.<br />
• The International Space Station orbits at 248<br />
miles above the Earth.<br />
• The axis of orbit of the planet Uranus is tilted at a<br />
90 degree angle.<br />
• Astronomers have discovered over 10,000<br />
asteroids - but put them together and they would<br />
be smaller than the Moon.<br />
• Have you ever seen a ring around the moon?<br />
Folklore has it that this means bad weather is<br />
coming.<br />
<strong>Xtra</strong><strong>Edge</strong> for IIT-JEE 15 FEBRUARY <strong>2012</strong>
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