Test Prep $-$ Part $1$

Multiple Cholee

Adentify the choice that best completes the statement or answers the question. $1HP=746$ wall or $\mathrm{.}7457$ Kw

$q,1.$ What is the effiency of $\frac{1}{2}Hp$ air conditioner which draws $10$ amperes at $120$ volts and has $60\%$ power factor?

a$.30\%$

c$.60\%$

b$.52\%$

d$.68\%$

$q,2.$ Conductance is the property of a circuit which tends to

a$.$ Permit the flow of electric current

c$.$ Permit the flow of magnetic flux

b$.$ Prevent the flow of electric current

d$.$ Prevent the flow of magnetic flux

$q,3.20$ lamps in parallel are connected across a $120$ volt line. If each lamp takes $0\mathrm{.}5$ amps and the voltage drop of the line is not to exceed $3\%$ of the line voltage, the resistance of each wire supplying the bank of lamps is most nearly

a$.0\mathrm{.}36$ ohm

c$.0\mathrm{.}24$ ohm

b$.0\mathrm{.}18$ ohm

d$.0\mathrm{.}12$ chm

$q,4.$ The output of a full wave rectifier is passed through a filter $($series$-$parallel combination of inductances and capacitors$)$ across which the load is connected. The main purpose of the filter is to

a$.$ Increase the frequency of the current

c$.$ increase the ripple voltage

b$.$ decrease the output waltage

d$.$ smooth the ripples

$q,5.$ The power consumed by a coil of wire having $110$ ohms impedance and $$0\%$ power factor on a $220-$volts A$.$C$.$ Line is most nearly

a$.225$ watts

c$.410$ watts

b$.350$ watts

d$.450$ watts

$q,6.$ The cold resistance, in ohms, of $60W,120$ Volt Tungsten lamp is

a$.240$

c$.$ Greater than the value of it hot resistance

b$.$ Equal to the value of its hat resistance

d$.$ Less than the value of its hot resistance

$q,7.$ A circult with a capacitor of $1\mathrm{.}0$ MFD is in series with a resistor of $10,000$ ohms. The circuit has a time

constant of

a$.10$ Nanoseconds

b$.10$ Milliseconds

c$.100$ Seconds

d$.10$ Gigaseconds

$1$