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atomic-structure

Particle A of mass $9m$ and particle $B$ of mass $m$ travel towards each other along a smooth horizontal surface in a straight line and collide head-on. The initial speed of particle A before the collision is $u$.\n\nIn Fig. 1.1, the variation with time $t$ of momentum $p$ is shown from $t=0$ to $t=3T$ for particle $A$ and from $t=0$ to $t=T$ for particle $B$.\n<img src="/serve/img-0_20250331210529562504.jpeg">\nFig. 1.1

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atomic-structure

A uniform square box with sides 0.80 m and mass 2.0 kg is at rest on the ground. One end of a light rope is attached to the box and the other end is attached to the wheel of a motor. The motor applies a constant clockwise torque of 5.0 N m on the wheel of radius 0.20 m .\n\nAt the instant shown in Fig. 2.1, the rope is taut and it makes an angle of $\theta =20^{\circ }$ with the vertical side of the box. The system remains in equilibrium.\n<img src="/serve/img-1_20250331210529564678.jpeg">\nFig. 2.1

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atomic-structure

A bob of mass 1.5 kg is attached to a string of negligible mass and of length 25.0 cm . The other end of the string is fixed to point $X$ of an inverted " $L$ " structure of arm length $d$. The structure is fixed to the centre of a rotating disc of radius 8.0 cm .\n\nWhen the disc rotates with an angular velocity $\omega$, the string makes at an angle $\theta$ to the vertical as shown in Fig. 3.1.\n<img src="/serve/img-2_20250331210529565031.jpeg">\nFig. 3.1

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(a) Explain why gravitational potential is always negative whereas electric potential can have positive and negative values, given that both potentials are zero at infinity.\n\n\n\n\n\n\n\n\n\n

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A transverse wave on a rope is travelling to the right. Fig. 5.1 shows the waveform at a particular time. Particles Q, R, S, T, U and V are labelled.\n<img src="/serve/img-4_20250331210529567662.jpeg">\nFig. 5.1

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Fig 6.1 shows a miniature E10 filament light bulb with a rating of $6.0\mathrm{V},3.0\mathrm{W}$.<img src="/serve/img-5_20250331210529568075.jpeg">\nFig. 6.1

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atomic-structure

A medical treatment makes use of a sample of americium-240 that emits alpha particles to kill cancer cells. In one such treatment, a total energy of 1140 J is applied to a tumour of mass 0.500 kg . At the start of the treatment, the mass of the americium-240 sample is $2.00\times 10^{-9}\mathrm{kg}$.\n\nAmericium-240 has a half-life of 50.2 hours, and it decays by emitting an alpha particle of kinetic energy 5.71 MeV .

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atomic-structure

Boron and its compounds have diverse applications across industries.

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atomic-structure

Water chemistry plays a critical role in the well-being of fishes in an aquarium. Fish waste releases ammonia into water which is toxic to fish. During nitrification, ammonia is broken down by beneficial bacteria into less toxic nitrate ions as shown in Fig. 2.1. <img src="/serve/img-4_20250404150227558834.jpeg"> Fig. 2.1

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This question explores the reactions of short-chain hydrocarbons and halogenoalkanes.

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(a) (i) Define the terms order of reaction and rate constant. [2] Question 4 continues on page 20.

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1 Boron and its compounds have diverse applications across industries.

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2 Water chemistry plays a critical role in the well-being of fishes in an aquarium. Fish waste releases ammonia into water which is toxic to fish. During nitrification, ammonia is broken down by beneficial bacteria into less toxic nitrate ions as shown in Fig. 2.1. <img src="/serve/img-4_20250404151637119261.jpeg"> Fig. 2.1

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3 This question explores the reactions of short-chain hydrocarbons and halogenoalkanes.

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4 (a) (i) Define the terms order of reaction and rate constant. $\qquad [2] Question 4 continues on page 20.

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Boron and its compounds have diverse applications across industries.