[OCR] 6
Topic: Atomic Structure
Fig 6.1 shows a miniature E10 filament light bulb with a rating of $6.0 \mathrm{~V}, 3.0 \mathrm{~W}$.
\nFig. 6.1
[16.0m]
Part 1: (a) (i) Calculate the resistance of the bulb.\n$$\text { resistance }=\ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots$$ [2m]
Part 2: (ii) The filament of the bulb is made of tungsten wire of length 2.0 cm and diameter $78 \mu \mathrm{m}$.\n\nCalculate the resistivity of the tungsten filament.\n$$\text { resistivity }=\ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots$$ [3m]
Part 3: (iii) The resistivity of tungsten from a table of constants is stated to be $5.6 \times 10^{-8} \Omega \mathrm{m}$.\n\nExplain, in microscopic terms, the difference between this value and your answer in (a)(ii). [3m]
Part 4: (b) Six identical E10 light bulbs are connected to a 6.0 V d.c. supply of negligible internal resistance in the arrangement shown in Fig. 6.2.\n
\nFig. 6.2\nAssume that the resistance of each bulb is as calculated in (a)(i).
[1m]
Part 5: (i) Determine the amount of charge that passes through bulb $Y$ in 2 minutes.\n$$\text { charge }=$$ [2m]
Part 6: (ii) Explain how the mean drift velocity of the electrons in the filament of bulb $Y$ compare with that of the electrons in the filament of bulb Z. [2m]
Part 7: (c) The six E10 light bulbs are now connected to an alternating power supply with frequency 50 Hz and r.m.s. voltage 6.0 V . An ideal diode is connected in parallel to bulb $Z$ as shown in Fig. 6.3.\n
\nFig. 6.3
[1m]
Part 8: On Fig. 6.4, sketch the variation with time $t$ of the power $P$ dissipated in bulb $Y$ from $t=0 \mathrm{~s}$ to $t=0.04 \mathrm{~s}$.\n\nInclude appropriate values for power on the vertical axis.\n
\nFig. 6.4
[2m]
Review
You're all caught up!
Similar Problems
OCR
Atomic Structure
Particle A of mass $9 m$ 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 $t=3 T$ for particle $A$ and from $t=0$ to $t=T$ for particle $B$.\n<img src="/serve/img-0_20250331210529562504.jpeg">\nFig. 1.1
OCR
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
OCR
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
OCR
Atomic Structure
(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$\qquad$\n$\qquad$\n$\qquad$\n$\qquad$\n$\qquad$\n$\qquad$\n$\qquad$\n$\qquad$\n$\qquad$\n$\qquad$
OCR
Atomic Structure
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
OCR
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 .
Atomic Structure
Read the passage below and answer the questions that follow.\nDespite the increasing popularity of laser printers