Class 11th

A circular coil has moment of inertia 0.8 kg m² around any diameter and is carrying current to produce a magnetic moment of 20Am². The coil is kept initially in a vertical position and it can rotate freely around a horizontal diameter. When a uniform magnetic field of 4 T is applied along the vertical, it starts rotating around its horizontal diameter. The angular speed the coil acquires after rotating by 60° will be:

Consider two uniform discs of the same thickness and different radii R₁ = R and R₂ = aR made of the same material. If the ratio of their moments of inertia I₁ and I₂, respectively, about their axes is I₁:I₂ = 1:16 then the value of a is:

Three rods of identical cross-section and lengths are made of three different materials of thermal conductivity K₁, K₂, and K₃, respectively. They are joined together at their ends to make a long rod (see figure). One end of the long rod is maintained at 100°C and the other at 0°C (see figure). If the joints of the rod are at 70°C and 20°C in steady state and there is no loss of energy from the surface of the rod, the correct relationship between K₁, K₂ and K₃ is:

The ionic radii of O²¯, F¯, Na+and Mg2+ are in the order:

On heating, lead (II) nitrate gives a brown gas (A). The gas (A) on cooling changes to a colourless solid/liquid (B). (B) on heating with NO changes to a blue solid (C). The oxidation number of nitrogen in solid (C) is:

The region in the electromagnetic spectrum where the Balmer series lines appear is:

Let (2x² + 3x + 4)¹⁰ = ∑ᵣ=₀²⁰ aᵣxʳ. Then a₁₃/a₁₁ is equal to

A survey shows that 63% of the people in a city read newspaper A whereas 76% read newspaper B. if x% of the people read both the newspapers, then a possible value of x can be:

The value of ∑ᵣ=₀²⁰ 50-rC₆ is equal to:

Let P(3,3) be a point on the hyperbola, x²/a² - y²/b² = 1. If the normal to it at P intersects the x-axis at (9,0) and e is its eccentricity, then the ordered pair (a², e²) is equal to: