MSBTE Exam Imp. Questions Physics PDF

Basic science (Physics ) SEM-I Q.1 Syrings of all types works on the principle of......... a) Boyle's law b) Charle's law c) Guy Lussac's law d) Coulomb’s law Answer: a) Boyle's law Explanation: Syringes operate based on Boyle's law, which states that pressure and volume of a gas are invers...

Basic science (Physics ) SEM-I Q.1 Syrings of all types works on the principle of......... a) Boyle's law b) Charle's law c) Guy Lussac's law d) Coulomb’s law Answer: a) Boyle's law Explanation: Syringes operate based on Boyle's law, which states that pressure and volume of a gas are inversely proportional at constant temperature. Pulling the plunger increases the volume inside the syringe, reducing pressure and drawing fluid in. Q.2 The temperature gradient for a metal rod of thickness 40cm is 3ºC/cm. If one of its ends is at 90° C, then the temperature of the other end will be……. Answer: 90°C - (3ºC/cm × 40 cm) = 90°C - 120°C = -30°C Explanation: The temperature at the other end is calculated using the gradient ΔT=gradient×distance\Delta T = \text{gradient} \times \text{distance}ΔT=gradient×distance. Q.3 In case of forward biased p-n junction diode, the current flowing through the diode......... if the applied voltage is beyond the knee voltage of the diode. a) Decreases b) increases c) Remains same d) initially decreases and finally increases Answer: b) increases Explanation: Once the voltage exceeds the knee voltage, the diode starts conducting significantly, and the current increases exponentially. Q.4 The number of electrons in the valence shell of an intrinsic semiconductor will be……….. a) less than 4 b) more than 4 (c) is equal to 4 (d) None of the these Answer: c) 4 Explanation: In intrinsic semiconductors like silicon or germanium, each atom has four electrons in its valence shell. Q.5 The reverse biased p-n junction diode acts as.......... a) closed switch b) open switch c) both open as well as closed switch Answer: b) open switch Explanation: In reverse bias, the diode prevents current flow, acting as an open circuit. Q.6 In case of reverse biased p-n junction diode, the resistance is............. a) Low b) zero c) less than one d) high Answer: a) high Explanation: The resistance is high in reverse bias due to minimal current flow. Q.7 The reverse breakdown voltage for a p-n junction diode is 40V. If it is operated at 20 V. it will act as........ a) open switch b) closed switch but will not get damaged c) both open as well as closed switch d) switch and will get damaged Answer: a) open switch Explanation: At a voltage below breakdown, the diode does not conduct significantly, acting as an open switch. Q.8 If the voltage of 0.4V is applied across Ge diode, it will act as........... a) open switch b) insulator c) both open as well as closed switch d) closed switch Answer: d) closed switch Explanation: Germanium (Ge) diodes have a threshold voltage of approximately 0.3– 0.4V, so at 0.4V, the diode conducts and acts as a closed switch. Q.9 When two resistances are connected in series, their equivalent resistance is 100 ohm and when connected in parallel to each other its value is 24 ohm. Therefore the two resistances are……… a) 20, 80 b) 30, 70 c) 40, 60 d) 50, 50 Answer: c) 40, 60 Explanation: Let the resistances be R1 and R2. 1. Series:(Rs) R1+R2=100 2. Parallel: (Rp) R1⋅R2/(R1+R2)=24 Q1: Syringes of all types work on the principle of………… Answer: a) Boyle's law Explanation: Syringes operate based on Boyle's law, which states that pressure and volume of a gas are inversely proportional at constant temperature. Pulling the plunger increases the volume inside the syringe, reducing pressure and drawing fluid in. Q2: The temperature gradient for a metal rod of thickness 40 cm is 3ºC/cm. If one of its ends is at 90ºC, then the temperature of the other end will be:…………. Answer: 90°C - (3ºC/cm × 40 cm) = 90°C - 120°C = -30°C Explanation: The temperature at the other end is calculated using the gradient ΔT=gradient×distance\Delta T = \text{gradient} \times \text{distance}ΔT=gradient×distance. Q3: In the case of a forward-biased p-n junction diode, the current flowing through the diode __________ if the applied voltage is beyond the knee voltage of the diode. Answer: b) increases Explanation: Once the voltage exceeds the knee voltage, the diode starts conducting significantly, and the current increases exponentially. Q4: The number of electrons in the valence shell of an intrinsic semiconductor will be: Answer: c) 4 Explanation: In intrinsic semiconductors like silicon or germanium, each atom has four electrons in its valence shell. Q5: The reverse-biased p-n junction diode acts as:………. Answer: b) open switch Explanation: In reverse bias, the diode prevents current flow, acting as an open circuit. Q6: In case of a reverse-biased p-n junction diode, the resistance is:…….. Answer: a) high Explanation: The resistance is high in reverse bias due to minimal current flow. Q7: The reverse breakdown voltage for a p-n junction diode is 40V. If it is operated at 20V, it will act as: Answer: a) open switch Explanation: At a voltage below breakdown, the diode does not conduct significantly, acting as an open switch. Q8: If the voltage of 0.4V is applied across a Ge diode, it will act as: Answer: d) closed switch Explanation: Germanium (Ge) diodes have a threshold voltage of approximately 0.3–0.4V, so at 0.4V, the diode conducts and acts as a closed switch. Q9: When two resistances are connected in series, their equivalent resistance is 100 ohms, and when connected in parallel, it is 24 ohms. Therefore, the two resistances are: Answer: c) 40, 60 Explanation: Let the resistances be R1 and R2. 3. Series:(Rs) R1+R2=100 4. Parallel: (Rp) R1⋅R2/(R1+R2)=24 Applied science (Physics) SEM-II Q.1 calculate the operating voltage of an X ray tube which emits X rays of wavelength 0.1 Angstrom. a) 1,24000V b) 124 kV c) Both (A) and (B) d) 1240 KV Q.2 The threshold wavelength for a certain metal is 2750 Angstrom, the minimum energy of photo producing the photo effect is………. a) 0.0045 eV b) 0.0045eV c) 0.045 eV d) 4.5 eV Q.3 If the wavelength of wave gets tripled when traveling from one medium into another, then its wave velocity a) becomes (1/3)rd of original b) becomes three times the original c) remains same d) None of the above Q.4 Two wires of same material and of lengths 1 m and 2m respectively have respective radij 2r and r. They are subjected to the same load. The respective ratio of their elongations is……. a) 8:1 b) 1:8 c) 4:1 d) 1:4 Q.5 The velocity of wave in a medium is 760 m/s. If 1800 waves passes through a point in the medium in one minute then wavelength of wave will be…….. a) 5.33 m b) 15.33 m c) 25.33 m d) 30.33m Q.6 object performing SHM has an acceleration of 0.2 m/s² at a distance of 0.05 m from mean position. The period of SHM is…………… second. a) Π /2 b) Π 3 c) Π /2 d) 2 Π Q.7 In which of the following, the cricket ball released by a bowler will remain in air for maximum time? a) When the ball is released from a height of 10m from ground, b) When the ball is released from a height of 20m from ground. c) When the ball is released from a height of 15m from ground. d) When the ball is released from a height of 7.5 m from ground. Q.8 A woman walks a distance of 5m with constant force of 10N. Work done by woman is………….. a) 50 J b) 50kJ c) 0.5J d) 0.5kJ Q.9 A bullet of mass 50 gm is fired with a velocity of 800 m/s from a gun of mass 5 kg. The velocity with which the gun will recoil is…… a) 8 cm/s  b) 8 m/s c) 8 m/s d) 80 m/s Q.10 A body is thrown in air at 45 degree with the horizontal.If it moves with velocity of 75m/sec, find the time of flight. (Take g=10m/sq.sec) a) 7.5 sec b) 1.060 sec c) 10.60sec d) 3.1 sec Q.11 The light incident on a photosensitive metal surface causes photoelectric emission. if the energy of incident photons is 10 eV and the maximum kinetic energy of emitted photoelectrons is 6eV. find the photoelectric work function of the metal surface …… a) 16 ev Q.12 The time period of particle in SHM is 0.1 sec. The frequency of motion is………… a) 1 Hz b) 5 Hz c) 10Hz d) 20Hz Q.13 When the force applied to a material results in change in its length, the corresponding stress is known as……… a) volume stress b) shear stress c) tensile stress Q.14 Power is defined as…….. a) Time per work done  b) Rate of work done w.r.t. time c) Amount of work done. d) Work done per unit mass Q.15 If person in a mall moves a trolley with a force of 60N and trolley moves through a distance of 2000 cm, work done will be…… a) 30 J b) 120000 J c) 1200 J Q.16 An electric kettle of 20W works for 10 minutes, energy consumed by kettle is............. a) 1200 J b) 2400 J c) 12 kJ Q.17 The volume stress is equal …………….to acting on a body. a) change in area b) change in pressure c) change in force d) change in less Q.18 The ratio of maximum load that a material can bear to the original cross sectional area is called as…… a) Working stress b) breaking stress c) factor of safety d) ultimate stress Q.19 1000 liters of water is pumped to a height of 50 m. The work done by the pump is............. (Take g= 9.81m / sq.sec) a) 9.8 * 105 * J  b) 4.9 * 105 erg c) 4.9 * 105 J d) 49 * 105 J Q.20 If bicycle of mass 15 kg moves at a speed of 50 m/s, find the kinetic energy of bicycle. a) 18750 J b) 375 J c) 37500 J d) 6000 J Q1. Calculate the operating voltage of an X-ray tube which emits X-rays of wavelength 0.1 Angstrom. Energy of emitted X-rays 𝐸=ℎ𝑐𝜆E= λhc, where ℎ=4.135×10−15 eV\cdotps h=4.135×10 −15 eV\cdotps, 𝑐=3×108m/sc=3×10 8 m/s, and 𝜆=0.1A˚=1×10−12 mλ=0.1 A˚=1×10 −12 m.𝐸=12400𝜆(A˚)=124000eV=124 kVE= λ( A˚ )12400=124000eV=124kV Answer: (c) Both (A) and (B) Q2. Threshold wavelength: 2750A˚2750 A˚.Calculate the minimum energy. Threshold energy 𝐸=ℎ𝑐𝜆E= λhc: 𝐸=124002750=4.5eV E= 275012400=4.5eV Answer: (d) 4.5 eV Q3. If the wavelength of a wave gets tripled, its wave velocity: Velocity of the wave 𝑣=𝑓𝜆 v=fλ. Since frequency remains constant, when 𝜆λ triples, 𝑣v also triples. Answer: (b) becomes three times the original Q4. Ratio of elongations of two wires: Elongation Δ𝐿∝𝐿𝐴ΔL∝ AL, where 𝐴∝𝑟2A∝r 2. For lengths 𝐿1=1,2=2mL 1 =1m,L 2 =2m and radii 𝑟1=2𝑟,𝑟2=𝑟r 1=2r,r =r:Δ𝐿1Δ𝐿2=𝐿1⋅𝑟22𝐿2⋅𝑟12=1⋅𝑟22⋅(2𝑟)2=18ΔL 2ΔL 1 = L⋅r 12L 1⋅r 22= 2⋅(2r) 2 1⋅r 2= 81 Answer: (b) 1:8 Q5. Wavelength of wave: Frequency 𝑓=Number of wavesTime=180060=30Hz Frequency f= TimeNumber of waves= 601800 =30Hz𝜆=𝑣𝑓=76030≈25.33 mλ= fv= 30760 ≈25.33m Answer: (c) 25.33 m Q6. Period of SHM: Acceleration 𝑎=𝜔2𝑥a=ω 2 x, 𝜔=𝑎𝑥=0.20.05=2 rad/sω= xa = 0.050.2=2rad/s. 𝑇=2𝜋𝜔=2𝜋2=𝜋 sT= ω2π = 22π=πs Answer: (d) 2𝜋2π Q7. Cricket ball in air for maximum time: Time of flight depends on the height. Higher the release height, longer the time of flight. Answer: (b) When the ball is released from a height of 20m from ground. Q8. Work done by the woman: 𝑊=𝐹⋅𝑑=10⋅5=5 J W=F⋅d=10⋅5=50J Answer: (a) 50 J Q9. Recoil velocity of the gun: By conservation of momentum: 𝑚bullet𝑣bullet=𝑚gun𝑣gunm bullet v bullet=m gunv gun𝑣 gun=𝑚bullet𝑣bullet𝑚gun=0.05⋅8005=8m/sv gun = m gun m bulletv bullet = 50.05⋅800 =8m/s Answer: (b) 8 m/s Q10. Time of flight: Time of flight 𝑇=2𝑢sin𝜃𝑔=2⋅75⋅sin45∘10T= g2usinθ= 102⋅75⋅sin45∘ :𝑇=2⋅75⋅1210=10.6sT= 102⋅75⋅ 21 =10.6s Answer: (c) 10.60 sec Q11. Work function of metal surface: 𝜙=𝐸incident−𝐾𝐸max=10−6=4eVϕ=E incident−KE max =10−6=4eV Answer: 4 eV Q12. Frequency of SHM: 𝑓=1/𝑇=10.1=10Hz f= T1 = 0.11 =10Hz Answer: (c) 10 Hz Q13. Stress causing change in length: Answer: (c) tensile stress Q14. Power definition: Answer: (b) Rate of work done w.r.t. time Q15. Work done in moving trolley: 𝑊=𝐹⋅𝑑=60⋅20=1200J W=F⋅d=60⋅20=1200J Answer: (c) 1200 J Q16. Energy consumed by kettle: 𝐸=𝑃⋅𝑡=20⋅600=12000J=12kJ E=P⋅t=20⋅600=12000J=12kJ Answer: (c) 12 kJ Q17. Volume stress is proportional to: Answer: (b) change in pressure Q18. Maximum load to cross-sectional area ratio: Answer: (b) breaking stress Q19. Work done by the pump: 𝑊=𝑚𝑔ℎ=(1000⋅9.81⋅50)=4.905×10 5J W=mgh=(1000⋅9.81⋅50)=4.905×10 5 J Answer: (c) 4.9×105 4.9×10 5 J Q20. Kinetic energy of the bicycle: 𝐾𝐸=1/2𝑚𝑣2=12⋅15⋅(50)2=18750J KE= 21 mv2 = 21⋅15⋅(50)2=18750J Answer: (a) 18750 J