TMA4/PHY192

My TMA Home TMA Results My Pending TMA Quick Help TMA Quiz Questions TMA: TMA4/PHY192 SCORE=9.00 PHY192 - Physics Practical II Mr. Ibanga Efiong (eibanga@noun.edu.ng ) 1 A convex mirror has a radius of 20 cm. An object is placed 30 cm in front of the mirror. Determine where the image will appear. −4.5cm$$-4.5cm$$ −5.5cm$$-5.5cm$$ −6.5cm$$-6.5cm$$ −7.5cm$$-7.5cm$$ 2 A wire of length L and cross-sectional area A has a resistivity ρ. Which of the following formulas can be used to calculate the resistance of the wire? Click here to see exhibit ρ×LA$$\frac{\rho \times L}{A}$$ ρ×AL$$\frac{\rho \times A}{L}$$ Lρ×A$$\frac{L}{\rho \times A}$$ No answer 3 The electric current as a function of voltage of a wire is presented by the attached graph.What is the resistance of the wire? Click here to see exhibit 1Ω$$1\mathrm{\Omega }$$ 1.02Ω$$1.02\mathrm{\Omega }$$ 1.6Ω$$1.6\mathrm{\Omega }$$ 0.8Ω$$0.8\mathrm{\Omega }$$ 4 An electrical source with internal resistance r is used to operate a lamp of resistance R. What fraction of the total power is delivered to the lamp? R+rR$$\frac{R+r}{R}$$ R−rR$$\frac{R-r}{R}$$ RR+r$$\frac{R}{R+r}$$ Rr$$\frac{R}{r}$$ 5 A battery of emf E and negligible internal resistance is connected to two resistances R1$$R_1$$ and R2$$R_2$$ in series. What the potential difference across R2$$R_2$$ ? E(R1+R2)R2$$\frac{E(R_1+R_2)}{R_2}$$ E(R1+R2)R1$$\frac{E(R_1+R_2)}{R_1}$$ ER2R1+R2$$\frac{E{R}_2}{R_1+R_2}$$ ER1R1+R2$$\frac{E{R}_1}{R_1+R_2}$$ 6 The electric current as a function of voltage of a wire is presented by the graph. What is the power dissipated in the resistor when the applied voltage is 5 V? Click here to see exhibit 5 W 10 W 15 W 20 W 7 Image formed by convex mirror for real object placed anywhere is ? Real Virtual Enlarged Inverted 8 Two wires P ad Q, each of the same length and same material, are connected in parallel to a battery. The diameter of P is half that of Q. What fraction of the total current passes through P? 0.2 0.25 0.33 0.5 9 Two resistances 2Ω$$2\mathrm{\Omega }$$ and 3Ω$$3\mathrm{\Omega }$$ are in parallel. The combination is in series with 1.5Ω$$1.5\mathrm{\Omega }$$ resistance and a power supply of voltage V. There is a current of 3A through the 2Ω$$2\mathrm{\Omega }$$ resistance. What are the values of the current I delivered by, and the voltage V across the power supply? 3A and 10.5V 4A and 9V 4A and 12V 12A and 18V 10 In an experiment to determine the relationship between the current I through a piece of tungsten wire and the potential difference V across it, the theoretical relationship used was I=kVn$$I=k{V}^n$$ , where k and n are constants which may be obtained from a straight line graph of the form y = mx + c, the symbols having their usual meaning. The corresponding linear equation for this experiment is ---------- I = nV + k 4I=nV2+k$$4I=n{V}^2+k$$ I=expVn+k$$I=exp{V}^n+k$$ logI = nlogV + logk 11 A current of 0.5A flowing through a wire produces 21J of heat in 1/2 min. The resistance of the wire is ----------- ohms to 1 place of decimal 2.8Ω$$2.8\mathrm{\Omega }$$ 3.2Ω$$3.2\mathrm{\Omega }$$ 1.4Ω$$1.4\mathrm{\Omega }$$ 4.6Ω$$4.6\mathrm{\Omega }$$ 12 Which of the following is not true about internal resistance. It is the opposition to the flow of current within a battery I=E/r+R$$I=E/r+R$$ is valid It is equal to emf Internal resistance is not the same as voltage 13 Beyond the critical angle, a ray of light moving from dense to rare medium suffers ----------- diffraction polarization total internal reflection total internal refraction 14 The physical phenomenon which accounts for apparent depth of a pool of water is called waves polariztion diffraction refraction 15 The ------------ of the eye plays an equivalent role of the screen in optical experiments lens iris optic nerve retina 16 Images formed by plane mirrors are ------------- real diminished enlarged laterally inverted 17 The physical principle which accounts for the travelling of sound through longer distances at night is called----------- waves polariztion diffraction refraction 18 A ray of light travels from air to glass. The incident ray makes an angle of 45 degrees while the refracted ray makes and angle of 30 degrees with the normal to the interface. The speed of light in air is 3.0×108m/s$$3.0\times {10}^{8}m/s$$ . What is the of speed of light in glass? 2.12×108m/s$$2.12\times {10}^{8}m/s$$ 4.24×108m/s$$4.24\times {10}^{8}m/s$$ 3.73×108/s$$3.73\times {10}^8/s$$ 3.00×108$/s$$3.00\times {10}^8\$/s$$ 19 A 9V battery is short-circuited. The potential difference across the battery is found to be 8V, and the current is 5A. What is the internal resistance of the battery? 0.1Ω$$0.1\mathrm{\Omega }$$ 0.2Ω$$0.2\mathrm{\Omega }$$ 0.3Ω$$0.3\mathrm{\Omega }$$ 0.4Ω$$0.4\mathrm{\Omega }$$ 20 Ohm's law relates potential difference with? power Energy current time