Post Utme Physics Past Questions and Answers

Question 576:

A reservoir $500\mathrm{m}$ deep is filled with a fluid of density $850{\mathrm{kgm}}^{-3}$. If the atmospheric pressure is $1.05\times {10}^5{\mathrm{Nm}}^{-2}$, the pressure at the bottom of the reservoir is ____________

$$[\mathrm{g}=10{\mathrm{ms}}^{-2}]$$

A. $4.72\times {10}^6{\mathrm{Nm}}^{-2}$
B. $4.36\times {10}^6{\mathrm{Nm}}^{-2}$
C. $4.28\times {10}^6{\mathrm{Nm}}^{-2}$
D. $4.25\times {10}^6{\mathrm{Nm}}^{-2}$

Question 577:

A string of length $4\mathrm{m}$ is extended by $0.02\mathrm{m}$ when a load of $0.4\mathrm{kg}$ is suspended at its end. What will be the length of the string when the applied force is $15\mathrm{N}?\left[\mathrm{g}10{\mathrm{ms}}^{-2}\right]$

A. $4.05\mathrm{m}$
B. $4.08\mathrm{m}$
C. $5.05\mathrm{m}$
D. $6.08\mathrm{m}$

Question 578:

A turning fork of frequency $340\mathrm{Hz}$ is vibrated just above cylindrical tube of height $1.2\mathrm{m}$, if water is slowly poured into the tube at what maximum height will resonance occur?

[speed of sound in air $=340{\mathrm{ms}}^{-1}$ ]

A. $0.45\mathrm{m}$
B. $0.95\mathrm{m}$
C. $0.60\mathrm{m}$
D. $0.50\mathrm{m}$

Question 579:

A wire of $50\mathrm{\Omega }$ resistances is drawn out so that its new length is twice the original length. If the resistivity of the wire remains the same and the cross-sectional area is halved, the new resistance is ____________

A. $200\mathrm{\Omega }$
B. $50\mathrm{\Omega }$
C. $40\mathrm{\Omega }$
D. $100\mathrm{\Omega }$

Question 580:

An electron of charge $1.6\times$ ${10}^{-19}$ is accelerated between 2 metal plates. If the kinetic energy of the electron is $4.8\times {10}^{-17}\mathrm{J}$, the potential difference between the plates is ____________

A. $300\mathrm{V}$
B. $30\mathrm{V}$
C. $400\mathrm{V}$
D. $40\mathrm{V}$