boyejo123:

I don't really get this sir where did you get 20 for object

it was a mistake I mean 120, not 20 since we said v equals u and v is 120cm, therefore u also equals 120cm so, 1/120+1/120 equals 1/f therefore, 2/120 is 1/f f equals 120/2, which is 60cm

DrBESTJC:
Please bosses here...

What is the lens formula for a concave or diverging lens ? ...Two textbooks I have are saying different things and I am confused..

1/u-1/v equals 1/f
Since v is negative, I guess

DrBESTJC:
Please bosses here...

What is the lens formula for a concave or diverging lens ? ...Two textbooks I have are saying different things and I am confused..

Don't be confused

1/f = 1/u + 1/v

However, in calculation the value of v is negativeand the value of F is negative because most images formed in a concave lens always give virtual, erect, and diminished image wherever the object is placed.

I prepared a free preparatory physics guide in pdf for students who want to download https://servantboy.com/category/physics-for-a-level-&-utme/

pabostt:


Don't be confused

1/f = 1/u + 1/v

However, in calculation the value of v is negativeand the value of F is negative because most images formed in a concave lens always give virtual, erect, and diminished image wherever the object is placed.

I prepared a free preparatory physics guide in pdf for students who want to download https://servantboy.com/category/physics-for-a-level-&-utme/

we are saying d same thing Sir, since V will eventually turns out to be negative, since it is diverging
so, it is safer to represent it directly with d negative notation from d formula to prevent time wasting

abeylysis92:


we are saying d same thing Sir, since V will eventually turns out to be negative, since it is diverging
so, it is safer to represent it directly with d negative notation from d formula to prevent time wasting

You are very right. I just use my comment to explain how the negative signs came to being.

abeylysis92:


1/u-1/v equals 1/f
Since v is negative, I guess

Yes, I know that V is negative...

But, What of 'f' ?

In as much as I know that the focal length of a diverging or concave lens is negative, some questions seem to deviate from that...Check out the questions below please...

pabostt:


Don't be confused

1/f = 1/u 1/v

However, in calculation the value of v is negativeand the value of F is negative because most images formed in a concave lens always give virtual, erect, and diminished image wherever the object is placed.

I prepared a free preparatory physics guide in pdf for students who want to download https://servantboy.com/category/physics-for-a-level-&-utme/

So you mean that the correct lens formula equation for concave or diverging lens is
- 1/f = 1/u - 1/v ??
If yes,that is what I already know !!...

But some questions seem to deviate from that...Eg:

1) Find the nature and position of the image of an object placed 6cm from a diverging lens of focal length 15cm.

Using your formula,I got 4.28,...but the textbook wrote -4.28 ...How come ?

2) For an object placed 6cm from a diverging lens of focal length 18cm,the image is :
A) 4.5cm in front of the lens
B) 4.5cm behind the lens
C) 9.0cm in front of the lens
D) 9.0cm behind the lens.

I also got 4.5cm here,but they wrote -4.5cm still picking (A) as the answer ...How come..?

Please Clarify...

DrBESTJC:


Yes, I know that V is negative...

But, What of 'f' ?

In as much as I know that the focal length of a diverging or concave lens is negative, some questions seem to deviate from that...Check out the questions below please...




So you mean that the correct lens formula equation for concave or diverging lens is
- 1/f = 1/u - 1/v ??
If yes,that is what I already know !!...

But some questions seem to deviate from that...Eg:

1) Find the nature and position of the image of an object placed 6cm from a diverging lens of focal length 15cm.

Using your formula,I got 4.28,...but the textbook wrote -4.28 ...How come ?

2) For an object placed 6cm from a diverging lens of focal length 18cm,the image is :
A) 4.5cm in front of the lens
B) 4.5cm behind the lens
C) 9.0cm in front of the lens
D) 9.0cm behind the lens.

I also got 4.5cm here,but they wrote -4.5cm still picking (A) as the answer [./b] ...How come..?

[b] Please Clarify...

To my understanding, to get the focal length of concave lens, v will be minus which makes the focal length negative . To question1 use:
1/f=1/u+1/v
but focal length of concave lens is negative
:1/15

DrBESTJC:


Yes, I know that V is negative...

But, What of 'f' ?

In as much as I know that the focal length of a diverging or concave lens is negative, some questions seem to deviate from that...Check out the questions below please...




So you mean that the correct lens formula equation for concave or diverging lens is
- 1/f = 1/u - 1/v ??
If yes,that is what I already know !!...

But some questions seem to deviate from that...Eg:

1) Find the nature and position of the image of an object placed 6cm from a diverging lens of focal length 15cm.

Using your formula,I got 4.28,...but the textbook wrote -4.28 ...How come ?

2) For an object placed 6cm from a diverging lens of focal length 18cm,the image is :
A) 4.5cm in front of the lens
B) 4.5cm behind the lens
C) 9.0cm in front of the lens
D) 9.0cm behind the lens.

I also got 4.5cm here,but they wrote -4.5cm still picking (A) as the answer [./b] ...How come..?

[b] Please Clarify...

To my understanding, to get the focal length of concave lens, v will be minus which makes the focal length negative . To question1 use:
1/f=1/u+1/v
but focal length of concave lens is negative
:-1/15=1/6+1/v
1/v=-1/15 -1/6
1/v=-6-15/90
1/v=-21/90
v=90/-21
v=-4.28cm

the lens formula does not change. Just know that for concave lens focal length is negative. what makes the image distance negative is the focal length which is negative and what makes the focal length negative is the negative image distance.

Join us this week for free Don't forget reg starts 5/9/2018 for this program

DrBESTJC:


Yes, I know that V is negative...

But, What of 'f' ?

In as much as I know that the focal length of a diverging or concave lens is negative, some questions seem to deviate from that...Check out the questions below please...




So you mean that the correct lens formula equation for concave or diverging lens is
- 1/f = 1/u - 1/v ??
If yes,that is what I already know !!...

But some questions seem to deviate from that...Eg:

1) Find the nature and position of the image of an object placed 6cm from a diverging lens of focal length 15cm.

Using your formula,I got 4.28,...but the textbook wrote -4.28 ...How come ?

2) For an object placed 6cm from a diverging lens of focal length 18cm,the image is :
A) 4.5cm in front of the lens
B) 4.5cm behind the lens
C) 9.0cm in front of the lens
D) 9.0cm behind the lens.

I also got 4.5cm here,but they wrote -4.5cm still picking (A) as the answer ...How come..?

Please Clarify...

To start with, the formula is
1/f = 1/u + 1/v
f = 18cm, which will become = -18cm
u = 6cm, which will remain the same
-1/18 = 1/6 + 1/v
-1/18 - 1/6 = 1/v
-4/18 = 1/v
v = -18/4 = -4.5 cm

This confirms that the image formed in a concave lens is virtual

Now if the question is, if the focal length is 15cm, the image distance is 4.5cm, find the object distance

the solution will be
f = 15cm which will become -15cm
v = 4.5 cm which will become -4.5cm
1/f = 1/u + 1/v
-1/18 = 1/u -1/4.5
1/u = 1/4.5 - 1/18

I hope you get the logic.

UI post UTME exact date and venue is out. check yours and reprint now.
Real Ul post UTME past questions available. whatsapp/call/SMS 08037737245 for more on how to get it. screenshots available for view too.
#No time

*A compilation of 2017/2018 UI Post-UTME with answers*

*Note: The questions were gotten from 2017/2018 candidates, so, you shouldn't expect 100% accuracy. And, the questions below weren't the only questions asked, you don't expect them to recall all the questions perfectly*

� If pico is 10–¹² then the prefix femto is _____ Answer == 10^–15.
� The standard time is defined as_____

�
A 3m ladder weighs 200N, a load of 50N was placed at one end and its centre of gravity is 120cm from the other end. Calculate the work done in raising the ladder from a horizontal to a vertical position.

Answer == The work done(against gravity) consists of two parts, the work done to raise the centre of gravity 1.20m and the work to raise the weight at the end through 3.0m. Therefore,

Work done = 200 × 1.20 + 50 × 3.0 = 0.39KJ.

� A clock was made by using a thin metal and a heavy mass as a pendulum. On a cold day the time will______

A) be shorter and gan time

B) be longer and gain time

C) be shorter and lose time

D) be longer and lose time

Answer=== A..
Note that for:

hot weather =>expansion =>loses time due to increase in diameter of the clock..

Cold weather =>contract =>gains time

� The penis of a reptile is called? *Hemipenes*

� A mass of 10Kg was placed on a table and acted upon a 10N Force to give an acceleration of 0.2ms–² calculate the coefficient of friction between the mass and the table.

Answer===From Newton's laws,

∑F = ma

P – Fr = ma

10 – Fr = 10(0.2)

10 – Fr = 2

Fr = 8N

μ = Fr/R

μ = 8/mg

μ = 8/100

μ = 0.08

� Arrange in decreasing order of acidity => NaCl, NaOH, HCl, CH3COOH, milk of magnesia

Answer==

HCl, CH3COOH, Milk of magnesia, NaCl, NaOH

� Whiich of the following animals retain the usage of gills throughout it's lifetime
A.whale B.TOAD C.SHARK D.TURTLE E.TADPOLE

Answer== Shark.. Whale is a mammal, so, it uses lungs throughout its lifetime.

� Twenty dollars _____ enough for me ( English)

Answer== *Is*

� ____ is used as fire extinguisher

A). CH3Cl2. B) CCl4. C).CHCl3 D CH2Cl2

Answer== CCl4( because of its non flammable nature)


� (Synonyms )
The performance of the students in the utme exam was UNPRECEDENTED
A. Shocking
B. Failure
C. Fair
D. First of its kind

Answer===�

� Which of the following is used as an anaesthesia?

A) CCl4 B) CH3Cl C) CHCl3 D CH2Cl2

Answer== Trichloromethane(CHCl3) Though it releases toxic gases when exposed to the atmosphere. But, due to the options provided, we actually need to go with CHCl3.

� *English*

My son, (who is in abroad), studied Medicine.
What is the grammatical name for the sentence in the bracket?

A. Non_Restrictive/Non_defining adjectival clause

B. Restrictive/Defining adjectival clause
C. Appositive

Answer =====�

� Biology :
-What is population?

-Which of the following plants is photosynthetic
A. Euglena B. Paramecium C. Chlamydomonas D. Amoeba

Answer== Clamydomonas. Though Amoeba possesses both plant and animal features... But, since they emphasized "plant", that makes Clamydomonas correct...

� Which of the following has the same sound as kEY
a. kiss b. quay c. keyed d. kissed

Answer== B� Waec 2016�

� Which of the following has the same sound as rEd
Answer==. read(past tense)

� The angle of incidence in a denser medium when the angle of refraction in the less dense
medium is 90° is called a
(A) Critical angle (B) Reflected angle (C) Incident angle (D) Emergent angle

Answer== A.

� A certain radioactive element has a half life of 20 years. How long will it take the activity to
become ¼ of its original?
(A) 20 years (B) 40 years (C) 60 years (D) 80 years

Answer== 40years.

� Not many women _____ bearded men
Likes
Like
liking

Answer== Like.

� Eng #In the US, one out of ten people ___ Bin Laden A. hate B. hates C. would hate D. will hate.

Answer== Hates(B).

� Which of the following does not undergo complete metamorphosis? a. cockroach b. mosquito c. housefly d. bee

Answer === Cockroach.
� One major difference between an Angiosperm and a Gymnosperm is that seeds in Gymnosperms
are borne in (A) Cones (B) fruits (C) flowers (D) ovary (E) ovule

Answer== A.

� CO(g) +H2O(g)===CO2(g) +H2(g)
From d reaction above, calculate the standard heat change if the standard enthalpies of formation of CO2(g),H2O nd CO in KJmol` are -394,-242 and -110 respectively.

A.+42 B. -198 C. -42 D. +198

Answer=== C.

� Which of the following is the strongest Base ?

A. NaOH
B. NaNH2
C. NaF

Answer=== B.

Out of O and N, Oxygen is more electronegative. Therefore, it attracts the shared electron pair of O-H bond more towards itself than N attracts it in N-H bond. As a result, O-H bond is more easily broken than N-H bond. and hence NaOH loses H atom more easily than NaNH2. Implies that NaOH is more acidic (less basic) than NaNH2. So, NaOH is also a base but NaNH2 is more basic.

� The reaction between chlorine nd hot concentrated alkali solution will give A .Cl` and H2O B .ClO3` and Cl` C. ClO3`, Cl` and H2O D.OCl`, Cl` and H2O

Answer=== 3Cl2 + 6NaOH(Hot conc) == NaClO3 + 5NaCl + 3H2O
*Option C*

� .The process by which nitrate is converted to nitrogen gas by certain bacteria is A. Nitrification B. Denitrification C. Nitrogen fixation D. Electrical discharge.

Answer== Option B


� In which part of d neurone is nucleus found A.Cell body B.Dendrite C.Myelin sheath D.Axon.

Answer== Option A.

� The value of half life is A. In2/lamda^2 B. In2/lamda C .2ln2/lamda^2 D. 1/2ln2/lamda^2

Answer== In2/Lambda *Option B*

� What is the important thing an epiphyte needs in a rainforest habitat. A. Water. B. Light. C. Host D. Temperature.

Answer=== Host. Light is ever sufficient for them, so they don't fight for it. They only struggle to get host which is much closer to where they can trap sunlight.

� Sulphides reacts with O2 to provide which main product

A. H2O

B. SO2

C. S

D. SO3

Answer === B.


� Which organism is photosynthetic? (a)amoeba(b)paramecium (c)euglena

Answer=== Euglena.

� Which of the following is highly specialize?
A. Amoeba B. Paramecium C. Euglena D. Plasmodium

Answer== Euglena

� Which of the following is true about about nuclear radiation?
I. Alpha particles are deflected in both electric and magnetic field
II. Electromagnetic ray are deflected in both electric and magnetic field
III. Beta particles are not deflected in both electric and magnetic field
A. I and II B. I only C.II and III D. I II and III


Answer=== Option B.

� In the nucleus of an atom, what force joins neutron and proton?

A) Electrostatic force B) Nuclear force C) Interatomic Force

Answer === Nuclear force.

� Pray to God and also trust in HIM for HIS to be done in this forth coming exam. Sincerely, you can't do it all alone. Ask for HIS unfeigned love, grave and mercies.

� Study hard for the exam as well.


*_NOTE: Kindly go through the answers provided, make corrections where needed. No one is perfect. A big thanks to those that give explanations to some of the questions last year_*


*FEEL FREE TO SHARE!!!*

Bosses pls come to my aid oo.

A horizontal force of 45N applied to a crate of mass 9kg is just sufficient to move it. If the crate is now pulled at an angle of 45 degrees, find the force required to move the crate over the horizontal surface
A. 43.86N
B.80.88N
C.63.86N
D.53.68N

exam date is out.....check yours now

@NTALIBAN,1 word 4 u "IT IS WELL WITH YOU". My exam is on 15th,faculty of vet med by 10:00am

.

How do I checked for my date of exam

MOG30:
How do I checked for my date of exam

log in to d reg portal and input ur details then print on "photo card"

MOG30:
How do I checked for my date of exam

Preferably use a system to check it using
admissions.ui.edu.ng/

Wanna join ui whatapp group pls

esivue007:
log in to d reg portal and input ur details then print on "photo card"

thanks bro i've seen it.

How to check my date of igzam pls
Help

Hardebaryor:
Bosses pls come to my aid oo.

A horizontal force of 45N applied to a crate of mass 9kg is just sufficient to move it. If the crate is now pulled at an angle of 45 degrees, find the force required to move the crate over the horizontal surface
A. 43.86N
B.80.88N
C.63.86N
D.53.68N

F - Fr = 0

45 - Fr = 0

Fr = 45N.

the force opposing the motion is 45N.
when the body was pulled at an angle 45° to the horizontal.

Fcos45 - Fr = 0

F = 45/cos45

F = 63.63N

Can wl check it through phone

Yes, @basitayoola7

basitayoola7:
Can wl check it through phone

has ui released d exams dates for each candidate

.

jerrykuvira:

has ui released d exams dates for each candidate

Haven't checked mine.....@NTALIBAN,1 word 4 u "IT IS WELL WITH YOU". My exam is on 15th,faculty of vet med by 10:00am my exam venue is vet 400lv class,seat no 10
It has been released..........ask the details from this guy

samuelizz:


F - Fr = 0

45 - Fr = 0

Fr = 45N.

the force opposing the motion is 45N.
when the body was pulled at an angle 45° to the horizontal.

Fcos45 - Fr = 0

F = 45/cos45

F = 63.63N

Thank you very mush

Hi UI aspirants.
Have you guys seen this?
https://www.nairaland.com/4705649/ui-aspirant-sci-department-check

basitayoola7:
Haven't checked mine.....@NTALIBAN,1 word 4 u "IT IS WELL WITH YOU". My exam is on 15th,faculty of vet med by 10:00am my exam venue is vet 400lv class,seat no 10
It has been released..........ask the details from this guy

checked mine already.
10 am Friday ETF LLT