# What does periscope mean?

## What does periscope mean?

A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer’s current position. In its simplest form, it consists of an outer case with mirrors at each end set parallel to each other at a 45° angle.

## What is a periscope easy definition?

A periscope is an optical instrument that uses a system of prisms, lenses or mirrors to reflect images through a tube. Light from a distant object strikes the top mirror and is then reflected at an angle of 90 degrees down the periscope tube.

What does periscope mean in reading?

English Language Learners Definition of periscope : a long tube that contains lenses and mirrors and that is used to look over or around something and especially by a person in a submarine to see above the surface of the water.

What is periscope used for?

Periscope, optical instrument used in land and sea warfare, submarine navigation, and elsewhere to enable an observer to see his surroundings while remaining under cover, behind armour, or submerged.

### Where are periscopes used today?

Uses Of Periscope

• It is used in submarines to determine the distance of a torpedo and helps in deciding the right time for the attack.
• It is used in a nuclear reactor to observe the chemical reactions that are taking place.
• In military periscopes are used to observe from their hiding position.

### What mirror is used for periscope?

plane mirrors

What is the mirror formula?

Suppose an object is placed u cm in front of a spherical mirror of focal length f such that the image is formed v cm from the mirror, then u, v and f are related by the equation; 1/f= 1/u + 1/v. This equation is referred to as the mirror formula. The formula holds for both concave and convex mirrors.

What is V and U in light?

Where v is the image distance and u is the object distance. Hence, the expression for magnification (m) becomes: m = h’/h = -v/u. Learn more about Reflection of Light here.

Convex mirror

## Is U positive in concave mirror?

Any distances measured on that side are positive. Distances measured on the other side are negative. f, the focal length, is positive for a concave mirror, and negative for a convex mirror. When the image distance is positive, the image is on the same side of the mirror as the object, and it is real and inverted.

What is the sign of concave mirror?

Since, object is always placed in front of the mirror hence the sign of object is taken as negative. Since, the centre of curvature and focus lie in front of the concave mirror, so signs of radius of curvature and focal length are taken as negative in the case of concave mirror.

What is U in concave mirror?

The distance between the object and the pole of the mirror is called the object distance(u). The distance between the image and the pole of the mirror is called Image distance(v). The distance between the Principal focus and pole of the mirror is called Focal Length(f).

### What is the applications of concave lens?

A concave lens is used to diverge incident rays. This helps to create a virtual image on the opposite side of the refracting surface. Hence, these lenses are used in binoculars, telescopes, cameras, flashlights and eyeglasses.

### What is another name of convex lens?

converging lens

What is the another name of concave mirror?

converging mirrors

Where do we use concave mirrors?

Concave mirrors are used as searchlights, shaving mirrors, satellite dishes, and many more. These mirrors have the property to collimate and concentrate light rays. Concave mirrors in torches and headlights are used as reflectors.

## Which are the places where mirror is used?

Mirrors commonly are placed in the bathroom or bedroom for the practical use of checking out your or your outfit while getting ready. Mirrors can be used in other parts of the home too. You can place a mirror in the hallway to make the smaller space appear larger.

# What does periscope mean?

## What does periscope mean?

A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer’s current position. In its simplest form, it consists of an outer case with mirrors at each end set parallel to each other at a 45° angle.

Where did the word periscope originate from?

periscope (n.) viewing apparatus on a submarine, by which objects in a horizontal view may be seen through a vertical tube, 1899, formed in English from peri- “around” + -scope “instrument for viewing.” Earlier (1865) a technical term in photography.

What is a periscope easy definition?

A periscope is an optical instrument that uses a system of prisms, lenses or mirrors to reflect images through a tube. Light from a distant object strikes the top mirror and is then reflected at an angle of 90 degrees down the periscope tube.

### What is another name for periscope?

Periscope Synonyms – WordHippo Thesaurus….What is another word for periscope?

finder bombsight
viewfinder homing device
telescopic sight

What is the opposite of Periscope?

We have listed all the opposite words for periscope alphabetically. loser. also-ran. deadbeat.

What does brusquely mean in English?

1 : markedly short and abrupt a brusque reply. 2 : blunt in manner or speech often to the point of ungracious harshness was brusque with the customers.

## What does imperious mean in English?

1a : marked by arrogant assurance : domineering. b : befitting or characteristic of one of eminent rank or attainments : commanding, dominant an imperious manner.

Is off-hand a correct English?

adjective. informal, casual, curt, or brusque: an offhand manner. Also offhanded. done or made offhand.

Do you know it offhand?

The phrase to say something ‘offhand’ means to say something or give information without checking first if the information is correct or accurate. If you ‘know something offhand’ it means you know the information correctly without checking.

### What is the opposite of off hand?

Antonyms: careful, prepared. Synonyms: unrehearsed, ad-lib, off-the-cuff, extemporaneous, extempore, offhand, extemporary, impromptu, offhanded.

What is an offhand voice?

an offhand tone of voice2 said or done without thinking or planning an offhand remark —offhandedly adverb —offhandedness noun [uncountable]Examples from the Corpusoffhand• There is sometimes a stage in the tone 2 are where the patient begins to be offhand and flippant.

Is Heart off or off hand?

“Offhead” is not a word. Nor is “offheart”; the phrase meaning “without needing to read the words” is “by heart”. Finally “I can recite the anthem offhand” doesn’t really mean the same as “by heart”.

## Why do we say off by heart?

This phrase means ‘to learn by the wheel’ – from ‘rota,’ the L*tin word for ‘wheel. ‘ The allusion is to turning the thought over and over in the mind or saying it over and over again, in much the same way as a wheel goes around.” From “Why do we say it?

What is the meaning of at heart?

used to say what someone is really like: He had dozens of friends, but he was a private person at heart.

What is the meaning of by heart?

phrase. If you know something such as a poem by heart, you have learned it so well that you can remember it without having to read it. Mack knew this passage by heart. Synonyms: from or by memory, verbatim, word for word, pat More Synonyms of by heart.

### Is it our heart or our hearts?

Reason: “Our” is a plural pronoun which requires the plural “hearts”. She will always live in my family members’ hearts. Reason: “Family members” is plural as you have various family members so is “hearts”. She will always live in my family’s heart.

Is it by heart or off by heart?

Grammatically speaking, the preposition “from” should be used. “I’ve got to learn these words (off) by heart in a very short time” and “You have to learn these two pages (off) by heart by tomorrow morning”, is correct.

What does you got it by heart mean?

Completely; by memory. Often used in reference to something that one has memorized or knows very well. Ask Becky to recite the poem—she knows it by heart.

## What does a lot of heart mean?

To have a lot of heart means to be particularly empathic, compassionate or loving.

What does heavy heart mean?

: a great deal of sadness It is with a heavy heart that I bring you this bad news. I announced my decision to leave with a heavy heart.

What does it mean spiritually when your heart is heavy?

In my opinion, a heavy heart or head is more than just a metaphor for mental or emotional distress. The feeling of heaviness always occurs owing to an excess of thoughts occupying our minds. On an average, it is estimated that we think 60,000 different thoughts each day.

### What does the Bible say about heavy heart?

“The Lord is my strength and my shield; my heart trusts in him, and he helps me. My heart leaps for joy, and with my song I praise him. The Lord is the strength of his people, a fortress of salvation for his anointed one.”

Why do I wake up with a heavy heart?

Many factors can cause a person to wake up with a racing heart, including diet, stress, sleep deprivation, and arrhythmia. Sometimes, upon waking, it may feel as though the heart is beating very fast or pounding in the chest. A person may also feel shaky or anxious when this happens.

What is a normal heart rate after waking up?

During your waking hours, the number of heartbeats per minute when you’re just sitting quietly is known as your resting heart rate. In most adults, resting heart rates range between 60 and 100 beats per minute. Once you stand up and move around, your heart rate goes up.

## Can lack of sleep cause heart palpitations?

Frequently, palpitations occur without any obvious precipitating factor, although fatigue, stress, and lack of sleep also cause palpitations to occur or worsen.

Why do I wake up shaking?

There are a number of reasons that we may wake up feeling shaky and experiencing trembling, and whilst this can be quite alarming, it is often not due to any emergency cause. The most common reasons that we may experience shaking are due to low blood sugar levels and anxiety, as you have mentioned.

Is shaking in your sleep normal?

If twitching in your sleep sounds familiar, don’t worry because you are not alone. According to LiveScience, 60-70% of people experience twitching in sleep and that’s only the number of people that manage to remember having these twitches in their sleepy state. Many hypnic jerks can go unregistered.