De thi KHTN Tieng Anh mon VL9

VINH BAO DIVISION OF
EDUCATION AND TRAINING

MATHEMATICS AND SCIENCE COMPETITION
IN ENGLISH, SCHOOL YEAR : 2018-2019
TEST: PHYSICAL

Circle letters precede the correct answer.
Question 1: The intensity of electric current through a circuit section
A. proportional to the voltage applied to both ends of circuits.
B. The rate inversely with the voltage applied to the first two circuits.
C. No change when changing the voltage applied to the first two circuits.
D. Decrease when the voltage increases in the first two circuits.
Question 2: This chart shows the dependence on the current intensity between the first
voltage wire form is
A. A line through the origin.
B. A straight line passing threugh the origin.
C. A curve passing through the origin.
D. A curve does not go through the origin.
Question 3: If you increase the voltage between the ends of a wire to4 times the intensity of
electric current running through wires changed how?
A. Increase 4 times B. Reduce 4 times
C. Increase2 times PB. Reduce 2 times
Question 4: When placed on the first two conductors_a 6V voltage, the current through it
intensity of 0.5 A. If the signal two first appliedvoltage 1s 24Vewires then pass it amperage is
A. 1,5 A.
B. 2,0 A.
C. 3,0.
D.1,0 A.
Question 5: Which of the following formula4ds used to determine electricity resistance of the
wire?

A. R==

B.R=U.I

CzR=~

D.R=5

Question 6: System following formula isthe expression of Ohm's law?

A. u=-

B.1=-

C.1=-

D. R=-

Question 7: Which of the following location where.n is a unit measuring the resistance?
A. Ohm(Q)
B. Wat (W)
C. Ampe (A)
D. Vol (V)
Question 8: The following formuladoes not fit.the formula with serial circuits?
A.I=li=l›

B.

[=],

+

C/U=

U; + U2

D. Rea
= Ri + Ro

Question 9: The two resistors‘Ri and R2 connected in series together. Voltages at both ends
of the resistors Ri and R2 U;/and U2 respectively. Said following relation correct?

ee a

B192

C/o ==

D.U,R, =U,R,

U,
U,
R,_
R,
R,
R,
Question 10: For Ri = 15Q, Ro = 25Q connected in succession, equivalent resistor value is:
A. 30Q
B. 10Q

C. 40Q
D. 9,375Q

Question 11: Two resistors Ri and’R2 = 2R: connected in series to the voltage of 12V. The

current through the circuit is O0SSA*The value of these two resistors is
A.Ri=8Q R2=160
B.R:=6OR:=l2O

C.Ri=4O Ra=8O
D.Ri=2Q R240
Question 12: Can determimesthe resistance of the wires of the following instruments?
A. Amplifier
B.Voltmeteryjand Amplifier
§C. Voltmeter
D. All are wrong
Question 13: Ri = 10QsR2= 15Q in parallel with each other. Equivalent resistance of
circuits with values is;
A. 25Q
B.12,50
C. 6Q
D. 3Q


Question 14: The formula is the formula for calculating equivalent resistance of two resistors
in parallel?

A.R=Ri+R.

B Reet

RR,

8 CR-_B®

R,+R,

Question 15: When R; is parallel to Ro:

A.I=h+b

B.U=U¡=U¿

C.2=2
2

1

D. R=:

R,—R,

D. Both
A, B.C

Question 16: For two resistors Ri = R2 = 20 Q, stuck on the ends A, B. Equivalent resistance

of the circuit section AB when the Ri parallel R2 1s:
A. 10Q
B. 20Q
C. 30Q

D. 40Q

Question 17: Two resistors Ri, R2 are in parallel with each other. KnowsRi = 6 Q, the

equivalent resistance of the circuit is Ria = 3 Q then Ra 1s
A.R2=2Q0
B. Ro =3,5 Q
C.Ra=4O
D.Rz=69
Question 18: There are two resistors Ri = 15Q, R2=30Q Ri knews only withstand the
maximum amperage is 4A, while R2 withstand largest amperageus 3A. Questions may have
two serial resistor on to two points with a maximum.voltageas how much?
A. 60V
B. 90V
C. 135V
D. 150V
Quesfion 19: The resistance of a conductor does not depend-ôn the following factors?
A. Wiring material
B,Volume of conductor
C. Wiring length
D..Wire cross section
Question 20: To find out the dependence ofthe resistance of wires in length, must be carried
experimented with the wires have characteristics?
A. The wires of the same section, is made from the same material but with different length.
B. The conductors of the same cross section, of the same length but are made of different

materials

C. The conductors of the same length, are made from the same material but different cross

section.

D. The wires of the same sectionMs made/from the same material and have the same length

Question 21: Two segments of.the same conductor cross-section and is made from the same
material but with a length respectively 1, 21.1f the conductor length | resistor R, the long wire
resistive 21 is how much?
A.R
B.4R
C.3R
D. 2R
Question 22: If the conductor cross section increases to 2 times the resistance:

A. Increase 2 times B. Reduce 24times
C. Increase 4 times D. Reduce 4 times
Question 23 A copper conductor fesistivity is 1,7.10°° Qm shall:
A. Copper shaped conductors/ length 1m, section 1m? with resistance of 1.7.10°Q
B. Copper shaped conductors, léngth 2m, section 1m? with resistance of 1.7.10°Q
C. Copper shaped conductors, length Im, section 0.5m? with resistance of 1.7.10°Q
D. Copper shaped conductorsy length 2m, section 2m? with resistance of 1.7.10°Q
Question 24: If reducing sugar conductor diameter 3 times the resistance of the wire
A. Increase 3 times B. Increase 9 times C. Reduce 3 times
D. Reduce 9 times
Question 25: Two copper wires of the same length. The first wire cross section S, = 0,5 mm?
and resistors Ri = 127,5Q. When the second wire has a resistance R2 = 8.5Q, the wire's crosssection receives the value of the following values

A.S2=7.5 mm?

~~ B.S2.=5mm/?

C. So = 15mm?

D. S2 = 10mm?

Question 26: A copper wire of length | = 100m has a cross section of 2mm7, knowing the
resistivity of copper is p = 1.7.10°° Qm. The resistance of the copper wire is:
A. 0.85.10° Q
B. 0.85 Q
C. 3.4.10° Q
D. 3.4Q


Question 27: The conductor length I, section S and made of substances resistivity p, the
resistor R is calculated by formula

A.R= p>

Ỉ

BR = >

pl

CR=

ps

D.R=ø“:
S

Question 28: Resistance is the resistor of a cylindrical conductor having:
A. Length Im, cross section is 1m’.
C. Length of Im, cross section 1s Imm’.

B. Length of Im, cross‘section 1s lcm’.
D. Length Imm, cross section Imm’.

Question 29: A copper wiring length 1 = 100cm, section 2 mm”, resistivity p = 1, 7:10 ° Om.
Resistance of the conductor is:
A. 8,5.10 7 Q.
B. 0,85.10°7Q.
C. 85.102O.
D20,085.10°7Q.
Question 30: A long metal wire 1; = 150 m, with cross secti6n $1 = 0,4 mm? and resistance

R; = 60 Q. Ask another wire made of metal thatdength l2 = 30m with resistance R2 = 30Q,
then section S2 is:
A. S2 = 0,8mm?
B.S2=0,16mm? = CSy/= 1,6mm?
D. S2 = 0,08mm?