# IB Physics Revision 2017

/The IB Physics examination papers are on October 31 and November 1. From now until this date I will list questions to help students revise for their Physics examination. This list will be updated over the next six weeks.

Students can increase their marks significantly during this period if they are positive, organised and have a plan. What is required is a balanced approach to study with adequate nutrition, sleep, exercise and recreation.

**Powers of Ten**The radius of a proton is 0.88 fm. What is the density of a proton in kg/m^{3}? (A) 10^{-6}, (B) 10^{2}, (C) 10^{10}, (D) 10^{18}, (E) 10^{26}**Uncertainty Analysis**The measured uncertainty in the length of a pendulum is 2%, the uncertainty in its mass is 3% and the uncertaity in the acceleration due to gravity is 4%. What is the percentage uncertainty in its period of oscillation? (A) 1% (B) 2%, (C) 3%, (D) 4%, (E) 5%**Dimensions**Surface tension is force per unit length. What are the dimensions of surface tension? (A)ML^{-2}(B)MT^{-2}(C)ML^{-2}T^{-2}(D)L^{-1}T^{-2}(E) ML^{-1}T^{-2}**Relative Velocity**At noon a ship S is 10 km west of a tanker T. The velocity of S relative to the Earth is constant at 12 km/h N30°E and the constant velocity of T relative to the Earth is 4.0 km/h S60°W. What is the distance between the vessels at 3pm on the same day? (A)3.2 km (B) 21 km (C) 41 km (D) 48 km (E) 58 km**Change in Velocity**A particle moves at a constant speed*v*around a circular path. What is the magnitude of its change in velocity after it turns through an angle 2𝜽? (A)*v*cos𝜽 (B)*v*sin𝜽 (c)2*v*cos𝜽 (D) 2*v*sin𝜽 (E)*v*sin2𝜽**Constant Acceleration**A stone is thrown vertically upwards from the edge of a building and strikes the ground after a time t_{1}. When the stone is thrown vertically downwards from the same point at the same initial speed it hits the ground after a time t_{2}. The time to fall if the stone was released from rest is (A) t_{1}+t_{2}(B) t_{1}-t_{2}(C) (t_{1}t_{2})^{1/2}(D) (2t_{1}t_{2})^{1/2}(E) (0.5t_{1}t_{2})^{1/2}**Resultant Force**A marble dropped from a height h above soft sand penetrates a distance d into the sand before comng to rest. If the marble is dropped from a height 2h the distance that it travels in the sand before coming to rest is (A) d (B) 2d^{1/2}(C) (2d)^{1/2}(D) 2^{1/2}d (E) 2d**Stretching a Spring**An unstretched spring of force constant*k*has one end tied to a vertical wall and a mass m at its other end. A constant horizontal stretching force*F*is applied to the mass. The extension of the spring in the horizontal direction when the mass comes to rest is (A) F/2k (B) F/k (C) 2F/k (D) 3F/k (E) 4F/k**Explosion**A mass*M*is initially at rest. It breaks up into two equal pieces having a total kinetic energy*E*. What is the magnitude of the relative velocity of the two pieces after explosion? (A)(2E/m)^{1/2}(B) (4E/m)^{1/2}(C) (8E/m)^{1/2}(D) (2m/E)^{1/2}(E) (4m/E)^{1/2}**Ideal Gas**Boltzmann's constant is equal to (A) R/N_{A}(B) RN_{A}(C) N_{A}/R (D) R+N_{A}(E) R/N_{A}^{2}**Ideal Gas Particles**A cylinder contains a volume V of helium gas at a temperature T. A second cylinder contains a volume 2V of argon gas at a temperature T. (A) the average speed of a helium atom is the same as that of an argon atom, (B) the average speed of a helium atom is less than that of an argon atom, (C) the average speed of a helium atom is greater than that of an argon atom, (D) each container contains the same number of particles, (E) the pressure exerted by each gas is the same**Change of State**A copper block is heated in a Bunsen flame. The copper block is then placed on a large block of ice at 0°C in which it becomes half buried. What was the initial temperature of the copper block? (A) 5°C (B) 22°C (C) 42°C (D) 62°C (E) 82°C**Specific Heat Capacity**One kilogram of copper and the same mass of water are heated using the same Bunsen burner. (A) the rate of temperature increase of both objects is the same, (B) the rate of temperature increase of water is greater than that of copper, (C) the rate of temperature increase of copper is greater than that of water, (D) the rate of internal energy increase is the same for each object, (E) the rate of internal energy increase for water is greater than that of copper.**Electric Current**Two copper wires, P and Q, at the same temperature have the same battery of zero internal resistance connected across each of them. The length of P is twice that of Q. The drift speed of the electrons in P is (A) the same as that in Q, (B) greater than that in Q, (C) less than that in Q (D) is zero (E) depends on the diameter of the wire.**Resistance**Four equal resistors R form the sides of a square. Another resistor R is placed across a diagonal of the square. What is the total resistance between the other two corners of the square? (A)R/4 (B) R/2 (C) R (D) 2R (E) 4R**Electric Field Strength**Point charges of +4Q and -Q are placed a distance d apart in a vacuum. The resultant electric field is zero at a distance (A)2d to the left of -Q (B) d to the left of -Q (C) d to the right of -Q (D) 1.5d to the right of -Q (E) 2d to the right of -Q**Electrical Power**A battery of emf 12V and constant internal resistance is connected to a 6Ω resistor. The power of the 6Ω resistor is greatest when the internal resistance is (A) 0Ω (B) 3Ω (C) 6Ω (D) 9Ω (E) 12Ω**Multiple Point Source Interference**Monochromatic, coherent light is produced by two point sources. The intensity of the maxima produced on a screen is I. The experiment is repeated using 4 point sources with the same source spacing. The intensity of the principal maxima on the screen is (A) I, (B) 2I, (C) 4I, (D) 8I (E) 16I**Secondary Maxima**The number of secondary maxima between the principal maxima in the interference pattern produced by 4 coherent, monochromatic point sources of light is (A) 0, (B) 1, (C) 2, (D) 3, (E) 4**Interference Pattern**Compared to the interference pattern produced by 2 coherent, monochromatic point sources the intereference pattern produced by 8 sources of the same spacing (A) has brighter principal maxima that are closer together, (B) has brighter principal maxima that are farther apart, (C) has brighter principal maxima that are the same distance apart, (D) has principal maxima of the same intensity that are the same distance apart, (E) has principal maxima of the same intensity that are the closer together.**Single Rectangular Slit Diffraction**Monochromatic light passes through a single narrow slit. The intensity pattern is observed on a screen at a large distance from the single slit. Why does the intensity not stay at zero after the central maximum?